debug: Add exception and resourceloader, remove dupe wgDebugLogFile
debug: Add exception and resourceloader, remove dupe wgDebugLogFile

* Remove duplicate assignment of $wgDebugLogFile.
* Filter group 'exception' and 'resourceloader' by default.
* Remove 'debug-' prefix from commented out example.

Change-Id: I1e494f3d16ffdb38919f1a70054778a77eae8694

ankita-kumari/mediawiki-vagrant,stuartbman/mediawiki-vagrant,wikimedia/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,wikimedia/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,HarriAlasi/wiki3dviewer,stuartbman/mediawiki-vagrant,wikimedia/mediawiki-vagrant,physikerwelt/DRMF-vagrant,physikerwelt/DRMF-vagrant,HarriAlasi/wiki3dviewer,stuartbman/mediawiki-vagrant,physikerwelt/DRMF-vagrant,stuartbman/mediawiki-vagrant,stuartbman/mediawiki-vagrant,HarriAlasi/wiki3dviewer,HarriAlasi/wiki3dviewer,wikimedia/mediawiki-vagrant,HarriAlasi/wiki3dviewer,stuartbman/mediawiki-vagrant,wikimedia/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,physikerwelt/DRMF-vagrant,HarriAlasi/wiki3dviewer,wikimedia/mediawiki-vagrant,stuartbman/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,HarriAlasi/wiki3dviewer