Fix #67417. HTTP header value of `If-Modified-Since` set by `get_url` does not follow HTTP protocol.

Fix #67417. HTTP header value of `If-Modified-Since` set by `get_url` does not follow HTTP protocol.

(cherry picked from commit 1097694)

v2.9.7
======

Minor Changes
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- 'Edit on GitHub' link for plugin, cli documentation fixed to navigate to correct plugin, cli source.
- Handle get_tags_for_object API correctly in vmware_rest_client.
- Remove redundant encoding in json.load call in ipa module_utils (ansible/ansible#66592).
- ansible-test - Upgrade OpenSUSE containers to use Leap 15.1.
- ansible-test now supports testing against RHEL 7.8 when using the ``--remote`` option.
- vmware_cluster - Document alternatives for deprecated parameters

Removed Features (previously deprecated)
----------------------------------------

- ldap_attr, ldap_entry - The ``params`` option has been removed in Ansible-2.10 as it circumvents Ansible's option handling.  Setting ``bind_pw`` with the ``params`` option was disallowed in Ansible-2.7, 2.8, and 2.9 as it was insecure.  For information about this policy, see the discussion at: https://meetbot.fedoraproject.org/ansible-meeting/2017-09-28/ansible_dev_meeting.2017-09-28-15.00.log.html This fixes CVE-2020-1746

Bugfixes
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- **security issue** - The ``subversion`` module provided the password via the svn command line option ``--password`` and can be retrieved from the host's /proc/<pid>/cmdline file. Update the module to use the secure ``--password-from-stdin`` option instead, and add a warning in the module and in the documentation if svn version is too old to support it. (CVE-2020-1739)

- **security issue** win_unzip - normalize paths in archive to ensure extracted files do not escape from the target directory (CVE-2020-1737)

- **security_issue** - create temporary vault file with strict permissions when editing and prevent race condition (CVE-2020-1740)
- Alter task_executor's start_connection to support newer modules from collections which expect to send task UUID.
- Ansible.ModuleUtils.WebRequest - actually set no proxy when ``use_proxy: no`` is set on a Windows module - ansible/ansible#68528
- Ensure DataLoader temp files are removed at appropriate times and that we observe the LOCAL_TMP setting.
- Ensure we don't allow ansible_facts subkey of ansible_facts to override top level, also fix 'deprefixing' to prevent key transforms.
- Ensure we get an error when creating a remote tmp if it already exists. CVE-2020-1733
- Fact Delegation - Add ability to indicate which facts must always be delegated. Primarily for ``discovered_interpreter_python`` right now, but extensible later. (ansible/ansible#61002)
- Fix nxos_lacp replace operation (ansible/ansible#64074).
- Handle equal sign in password while using passwordstore lookup plugin.
- In fetch action, avoid using slurp return to set up dest, also ensure no dir traversal CVE-2019-3828.
- In vmware_guest_network module use appropriate network while creating or reconfiguring (ansible/ansible#65968).
- Log additional messages from persistent connection modules that may be missed if the module fails or returns early.
- `vmware_content_deploy_template`'s `cluster` argument no longer fails with an error message about resource pools.
- ansible command now correctly sends v2_playbook_on_start to callbacks
- ansible-galaxy - Error when install finds a tar with a file that will be extracted outside the collection install directory - CVE-2020-10691
- ansible-galaxy collection - Preserve executable bit on build and preserve mode on install from what tar member is set to - ansible/ansible#68415
- dense callback - fix plugin access to its configuration variables and remove a warning message (ansible/ansible#64628).
- display - Improve method of removing extra new line after warnings so it does not break Tower/Runner (ansible/ansible#68517)
- docker connection plugin - do not prefix remote path if running on Windows containers.
- for those running uids for invalid users (containers), fallback to uid=<uid> when logging fixes
- get_url pass incorrect If-Modified-Since header (ansible/ansible#67417)
- mysql_user - Fix idempotence when long grant lists are used (ansible/ansible#68044)
- os_user_role - Fix os_user_role issue to grant a role in a domain.
- ovirt_storage_domain: fix update_check for warning_low_space
- purefa_snmp - Fix error when deleting a manager and when creating a v2c manager (ansible/ansible#68180)
- rabbitmq_policy - Fix version parsing for RabbitMQ 3.8.
- routeros_facts - Prevent crash of module when ``ipv6`` package is not installed
- setup.ps1 - Fix ``ansible_fqdn`` using the wrong values to build the actual DNS FQDN.