message: sync: Remove superfluous assert(..)
  The later "if (alreadyLocked != sharedowners.end()) ..." already
  handles the case that the assert fails - and will potentially print
  extra info.
diff: @@ -310,7 +310,6 @@ void CSharedCriticalSection::lock_shared()
  {
  boost::unique_lock<boost::mutex> lock(setlock);
  assert(exclusiveOwner != tid);
  - assert(sharedowners.find(tid) == sharedowners.end());
  auto alreadyLocked = sharedowners.find(tid);
  if (alreadyLocked != sharedowners.end())
  {
  