Fix some naming warnings
add message to test assertion
Remove a sequence of unnecessary "throws Exception"
Fix https://bugzilla.redhat.com/show_bug.cgi?id=927236 remove lock on PageSubscriptionImpl
Reasoning is as follows:
- the method just forwards the call to getPageInfo(boolean, long) which
  is /not/ synchronized on PageSubscriptionImpl but which synchronizes
  on "consumedPages".
- for all I can tell, at PageSubscriptionImpl we really only need to protect on consumedPages.