Check Redis is running before using rpush

[borpin]

emoncms/Modules/admin/admin_controller.php

Line 240 in 1f3e991

$redis->rpush("service-runner","$update_script $type $firmware>$update_logfile");

re https://community.openenergymonitor.org/t/cant-update-10-1-6-fleeting-php-errors/12296

The call to redis should first check for the service running else an exception is raised. Ideally this should inform the user how to perform a manual update.

Other places where this is called should also check for the redis service.

[TrystanLea]

Thanks @borpin

[TrystanLea]

Fixed 9ebd472