Get cancellation grace period correctly

This changes the logic of getting cancellation grace
period of task runner before closing it: to move the
liveness check into the cancel_all() method in the
scheduler rather than ask the resource if it's IN_PROGRESS.

Change-Id: Ia2a03de227ff15cdce1b3dbb6cd6bff6c5a50a15
Partial-Bug: 1693495
(cherry picked from commit 8c62e96947)

heat/engine/resource.py

@@ -1062,9 +1062,6 @@ class Resource(object):
                 )
 
     def cancel_grace_period(self):
-        if self.status != self.IN_PROGRESS:
-            return None
-
         canceller = getattr(self,
                             'handle_%s_cancel' % self.action.lower(),
                             None)

heat/engine/scheduler.py

@@ -473,7 +473,10 @@ class DependencyTaskGroup(object):
                 return grace_period
 
         for k, r in six.iteritems(self._runners):
-            gp = get_grace_period(k)
+            if not r.started() or r.done():
+                gp = None
+            else:
+                gp = get_grace_period(k)
             try:
                 r.cancel(grace_period=gp)
             except Exception as ex: