High: PE: Ensure that fencing has completed for stop actions on stonith-dependent resources (lf#2551)

stops didn't depend on STONITH before. For resources residing on OCFS2
(or affected by other distributed processes), these may not be able to
stop before STONITH has completed. If there were too many of them, they
might saturate the TE/LRM queues so the stonith actions would even get
run.

This ensures that relevant stop actions are ordered behind STONITH.

Mercurial revision: 147ea19bd0b4e4610e1cd5c8aa6d6a2601c3bd85