Change the global suspend event channel lock file to a per-domain lock file

This allows multiple guests to be migrated or protected by Remus
simultaneously.

Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
Acked-by: Brendan Cully <brendan@cs.ubc.ca>

tools/python/xen/lowlevel/checkpoint/libcheckpoint.c

@@ -360,7 +360,7 @@ static void release_suspend_evtchn(checkpoint_state *s)
 {
   /* TODO: teach xen to clean up if port is unbound */
   if (s->xce >= 0 && s->suspend_evtchn >= 0) {
-    xc_suspend_evtchn_release(s->xce, s->suspend_evtchn);
+    xc_suspend_evtchn_release(s->xce, s->domid, s->suspend_evtchn);
     s->suspend_evtchn = -1;
   }
 }