Use correct case for SpecialRecentChanges class in SpecialPageFactory::$mList

Was giving the following message in the debug log:
Class SpecialRecentchanges was loaded using incorrect case.

Change-Id: I11c90eebeed135d03cb326d484f849cae21d87da
Merge "Use correct case for SpecialRecentChanges class in SpecialPageFactory::$mList"