Switched to different datetime formatting in JSON.

We now use the same format as the Pillar API.

pillarsdk/utils.py

@@ -22,6 +22,8 @@ else:
     string_type = basestring
     text_type = unicode
 
+JSON_DATE_FORMAT = '%a, %d %b %Y %H:%M:%S GMT'
+
 
 class PillarJSONEncoder(json.JSONEncoder):
     """JSON encoder with support for Pillar resources."""
@@ -31,7 +33,7 @@ class PillarJSONEncoder(json.JSONEncoder):
         from .resource import Resource
 
         if isinstance(obj, datetime.datetime):
-            return obj.isoformat(' ')
+            return obj.strftime(JSON_DATE_FORMAT)
         if isinstance(obj, Resource):
             return obj.to_dict()