When Coq is reset-initialed by CoqIDE, do reset jobs counters

Coq is not going to send any feedback message for the
brute-force canceled jobs, given that the process was killed.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16780 85f007b7-540e-0410-9357-904b9bb8a0f7