Item12472: The store publishes readTopic of the store. which can be called directly and not via Meta. Calling this method would leave the meta object in an inconsistent state, because the loadedRev and isLatest would not be set. Change this so that readTopic is required to call Meta->setLoadStatus (it is, after all, the only place that knows what is really going on with the topic). Clean up encapsulation of the meta class while we're there.

git-svn-id: http://svn.foswiki.org/trunk/PlainFileStoreContrib@16655 0b4bb1d4-4e5a-0410-9cc4-b2b747904278