fix: prevent PHP notice when edit donor address

[ravinderk]

Bug Report

User Story

As an admin, I want to edit donor address without any PHP notice.

Current Behavior

I am getting PHP notice when edit donor address on PHP version 5.6.20:

[28-Jan-2019 06:21:24 UTC] PHP Strict standards:  Only variables should be passed by reference in /app/public/wp-content/plugins/give/includes/admin/admin-actions.php on line 876
[28-Jan-2019 06:21:24 UTC] PHP Stack trace:
[28-Jan-2019 06:21:24 UTC] PHP   1. {main}() /app/public/wp-admin/admin-ajax.php:0
[28-Jan-2019 06:21:24 UTC] PHP   2. do_action() /app/public/wp-admin/admin-ajax.php:99
[28-Jan-2019 06:21:24 UTC] PHP   3. WP_Hook->do_action() /app/public/wp-includes/plugin.php:453
[28-Jan-2019 06:21:24 UTC] PHP   4. WP_Hook->apply_filters() /app/public/wp-includes/class-wp-hook.php:310
[28-Jan-2019 06:21:24 UTC] PHP   5. call_user_func_array:{/app/public/wp-includes/class-wp-hook.php:286}() /app/public/wp-includes/class-wp-hook.php:286
[28-Jan-2019 06:21:24 UTC] PHP   6. __give_ajax_donor_manage_addresses() /app/public/wp-includes/class-wp-hook.php:286
[28-Jan-2019 06:21:24 UTC] PHP Strict standards:  Only variables should be passed by reference in /app/public/wp-content/plugins/give/includes/admin/admin-actions.php on line 879
[28-Jan-2019 06:21:24 UTC] PHP Stack trace:
[28-Jan-2019 06:21:24 UTC] PHP   1. {main}() /app/public/wp-admin/admin-ajax.php:0
[28-Jan-2019 06:21:24 UTC] PHP   2. do_action() /app/public/wp-admin/admin-ajax.php:99
[28-Jan-2019 06:21:24 UTC] PHP   3. WP_Hook->do_action() /app/public/wp-includes/plugin.php:453
[28-Jan-2019 06:21:24 UTC] PHP   4. WP_Hook->apply_filters() /app/public/wp-includes/class-wp-hook.php:310
[28-Jan-2019 06:21:24 UTC] PHP   5. call_user_func_array:{/app/public/wp-includes/class-wp-hook.php:286}() /app/public/wp-includes/class-wp-hook.php:286
[28-Jan-2019 06:21:24 UTC] PHP   6. __give_ajax_donor_manage_addresses() /app/public/wp-includes/class-wp-hook.php:286
[28-Jan-2019 06:21:24 UTC] PHP Strict standards:  Only variables should be passed by reference in /app/public/wp-content/plugins/give/includes/class-give-donor.php on line 1443
[28-Jan-2019 06:21:24 UTC] PHP Stack trace:
[28-Jan-2019 06:21:24 UTC] PHP   1. {main}() /app/public/wp-admin/admin-ajax.php:0
[28-Jan-2019 06:21:24 UTC] PHP   2. do_action() /app/public/wp-admin/admin-ajax.php:99
[28-Jan-2019 06:21:24 UTC] PHP   3. WP_Hook->do_action() /app/public/wp-includes/plugin.php:453
[28-Jan-2019 06:21:24 UTC] PHP   4. WP_Hook->apply_filters() /app/public/wp-includes/class-wp-hook.php:310
[28-Jan-2019 06:21:24 UTC] PHP   5. call_user_func_array:{/app/public/wp-includes/class-wp-hook.php:286}() /app/public/wp-includes/class-wp-hook.php:286
[28-Jan-2019 06:21:24 UTC] PHP   6. __give_ajax_donor_manage_addresses() /app/public/wp-includes/class-wp-hook.php:286
[28-Jan-2019 06:21:24 UTC] PHP   7. Give_Donor->update_address() /app/public/wp-content/plugins/give/includes/admin/admin-actions.php:981
[28-Jan-2019 06:21:24 UTC] PHP Strict standards:  Only variables should be passed by reference in /app/public/wp-content/plugins/give/includes/class-give-donor.php on line 1445
[28-Jan-2019 06:21:24 UTC] PHP Stack trace:
[28-Jan-2019 06:21:24 UTC] PHP   1. {main}() /app/public/wp-admin/admin-ajax.php:0
[28-Jan-2019 06:21:24 UTC] PHP   2. do_action() /app/public/wp-admin/admin-ajax.php:99
[28-Jan-2019 06:21:24 UTC] PHP   3. WP_Hook->do_action() /app/public/wp-includes/plugin.php:453
[28-Jan-2019 06:21:24 UTC] PHP   4. WP_Hook->apply_filters() /app/public/wp-includes/class-wp-hook.php:310
[28-Jan-2019 06:21:24 UTC] PHP   5. call_user_func_array:{/app/public/wp-includes/class-wp-hook.php:286}() /app/public/wp-includes/class-wp-hook.php:286
[28-Jan-2019 06:21:24 UTC] PHP   6. __give_ajax_donor_manage_addresses() /app/public/wp-includes/class-wp-hook.php:286
[28-Jan-2019 06:21:24 UTC] PHP   7. Give_Donor->update_address() /app/public/wp-content/plugins/give/includes/admin/admin-actions.php:981
[28-Jan-2019 06:21:24 UTC] PHP Strict standards:  Only variables should be passed by reference in /app/public/wp-content/plugins/give/includes/class-give-donor.php on line 1324
[28-Jan-2019 06:21:24 UTC] PHP Stack trace:
[28-Jan-2019 06:21:24 UTC] PHP   1. {main}() /app/public/wp-admin/admin-ajax.php:0
[28-Jan-2019 06:21:24 UTC] PHP   2. do_action() /app/public/wp-admin/admin-ajax.php:99
[28-Jan-2019 06:21:24 UTC] PHP   3. WP_Hook->do_action() /app/public/wp-includes/plugin.php:453
[28-Jan-2019 06:21:24 UTC] PHP   4. WP_Hook->apply_filters() /app/public/wp-includes/class-wp-hook.php:310
[28-Jan-2019 06:21:24 UTC] PHP   5. call_user_func_array:{/app/public/wp-includes/class-wp-hook.php:286}() /app/public/wp-includes/class-wp-hook.php:286
[28-Jan-2019 06:21:24 UTC] PHP   6. __give_ajax_donor_manage_addresses() /app/public/wp-includes/class-wp-hook.php:286
[28-Jan-2019 06:21:24 UTC] PHP   7. Give_Donor->update_address() /app/public/wp-content/plugins/give/includes/admin/admin-actions.php:981
[28-Jan-2019 06:21:24 UTC] PHP   8. Give_Donor->add_address() /app/public/wp-content/plugins/give/includes/class-give-donor.php:1469
[28-Jan-2019 06:21:24 UTC] PHP Strict standards:  Only variables should be passed by reference in /app/public/wp-content/plugins/give/includes/class-give-donor.php on line 1326
[28-Jan-2019 06:21:24 UTC] PHP Stack trace:
[28-Jan-2019 06:21:24 UTC] PHP   1. {main}() /app/public/wp-admin/admin-ajax.php:0
[28-Jan-2019 06:21:24 UTC] PHP   2. do_action() /app/public/wp-admin/admin-ajax.php:99
[28-Jan-2019 06:21:24 UTC] PHP   3. WP_Hook->do_action() /app/public/wp-includes/plugin.php:453
[28-Jan-2019 06:21:24 UTC] PHP   4. WP_Hook->apply_filters() /app/public/wp-includes/class-wp-hook.php:310
[28-Jan-2019 06:21:24 UTC] PHP   5. call_user_func_array:{/app/public/wp-includes/class-wp-hook.php:286}() /app/public/wp-includes/class-wp-hook.php:286
[28-Jan-2019 06:21:24 UTC] PHP   6. __give_ajax_donor_manage_addresses() /app/public/wp-includes/class-wp-hook.php:286
[28-Jan-2019 06:21:24 UTC] PHP   7. Give_Donor->update_address() /app/public/wp-content/plugins/give/includes/admin/admin-actions.php:981
[28-Jan-2019 06:21:24 UTC] PHP   8. Give_Donor->add_address() /app/public/wp-content/plugins/give/includes/class-give-donor.php:1469

Bug Type

• This bug describes functionality that once worked as expected in version X.X.X.
• This bug describes functionality that never worked as expected.
• I am not sure whether this functionality ever worked as expected.

Acceptance Criteria

• Edit donor address without any PHP notice