To allow plays using different user accounts in the same playbook to function,…

To allow plays using different user accounts in the same playbook to function, clear the setup cache
between plays.

lib/ansible/playbook/__init__.py

@@ -122,6 +122,7 @@ class PlayBook(object):
         # loop through all patterns and run them
         self.callbacks.on_start()
         for play_ds in self.playbook:
+            self.SETUP_CACHE = {}
             self._run_play(Play(self,play_ds))
 
         # summarize the results