php log_driver: Pass all logs to php's configured error_log

[noobish]

As a sysadmin, it's super annoying to find that application X's php errors are not going to their expected location. In my case, that would be what I configured in php.ini or .htaccess.

With this, users are not forced into choosing an additional error_log file. They can choose 'php' for log_driver and let php's configured error_log function as they'd expect.

As an added bonus it also allows the error_log override in .htaccess to take effect (if configured) and route ALL log messages to the expected file (roundcube internal and php).

If you want to go overboard with overrides, you could also add a 'sapi' value with:
return error_log($line, 4);

[dereks]

Thank you for submitting a Pull Request (PR) to the Roundcube GitHub project.

You are receiving this message because your PR has conflicts which need to be resolved. We are trying to catch up on our backlog of old PRs and get them merged in (where appropriate). Therefor, we request the following:

Step 1. Rebase from the latest Roundcube branch master into your PR.

git fetch upstream
git checkout your_feature_branch_name
git rebase upstream/master
git push -f origin your_feature_branch_name

Step 2. Re-test to make sure your new code still works as expected

Step 3. Comment back here once it has been tested and will merge cleanly.

Once this has been done we will treat it like a new Pull Request and consider it for acceptance.

Apologies for the inconvenience. Thank you for contributing to Roundcube!