- Fix a problem with TQSlotPool inheriting from THashTable
  but having no ClassDef(). This was making crash at
  destruction time, the class scheme being wrong.
  Creating a THashTable private data member instead of
  inheriting from it solves the problem. Thanks to Andrei for
  the report.


git-svn-id: http://root.cern.ch/svn/root/trunk@24199 27541ba8-7e3a-0410-8455-c3a389f83636