Updated mediawiki/extensions
Project: mediawiki/extensions/Flow  48902281c81977d5197f7d65659f759ebc3212eb

Make header use *ActionPermissions

Renamed PostActionPermissions to more general RevisionActionPermissions & made
it accept any AbstractRevision object (that's where the moderation lives anyway)

Changed header code to use this class.

Made the class accept null for revision (like for checking permissions to create
a post/header)

Change-Id: Ic173c47f90b6ac1c7b7dd80befef34bdced23d66