Unblock skipped tests in test_action_defaults.py
Unblock skipped tests in test_action_defaults.py

* It now makes sense because https://bugs.launchpad.net/mistral/+bug/1517020
  is closed.

Change-Id: I9294ef9254df7015202926685da6cf8d670eaa57

openstack/mistral,StackStorm/mistral,StackStorm/mistral,openstack/mistral