From Gerri:

introduce single shot timer for proofserv termination. This timer makes
sure that there is still at least on item the will make DispatchOneEvent
return as all sockets are already closed.


git-svn-id: http://root.cern.ch/svn/root/trunk@17689 27541ba8-7e3a-0410-8455-c3a389f83636