Item12104: Remove LogDispatchContrib from MANIFEST

Log::Dispatch requires  Class::Load.  A decision was made at the
FoswikiCamp to remove Class::Load from dependencies, so we can't
retain LogDispatchContrib.

git-svn-id: http://svn.foswiki.org/trunk/core@17530 0b4bb1d4-4e5a-0410-9cc4-b2b747904278