Fastopen/InvokeTool: Don't try to invoke a non-existent tool
http://bugs.activestate.com/show_bug.cgi?id=100181

(integrated from komodo (trunk) change 81612 by ericp)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@13532 b87d16e7-d29f-4ee1-b5ec-817d645d335f