Pass-in the initial value when performing a POST on Workflow Action. …

…This fixes the call to self.changed_data, it allows django forms to be able to compare initial value with current value.

Fixes bug 1153697.

Change-Id: I21846487ada34f3b007a545bcdcba400bd044af5

horizon/workflows/base.py

@@ -129,7 +129,7 @@ class within them:
 
     def __init__(self, request, context, *args, **kwargs):
         if request.method == "POST":
-            super(Action, self).__init__(request.POST)
+            super(Action, self).__init__(request.POST, initial=context)
         else:
             super(Action, self).__init__(initial=context)