Updated mediawiki/extensions
Project: mediawiki/extensions/Flow  7c992292576f33187ad11c3307205de3dfa96112

Require getRevisionType in classes that extend AbstractRevision

That method is there in both PostRevision & Header, but we should make it more
explicit that it's needed (especially since AbstractRevision::toStorageRow calls
it)

Change-Id: Ic034a7bfe45fe713bf4ced500c916911af8ee879