Fix small decorator issue

docker/utils/decorators.py

@@ -11,11 +11,11 @@ def check_resource(f):
                 resource_id = kwargs.pop('container')
             elif kwargs.get('image'):
                 resource_id = kwargs.pop('image')
+        if isinstance(resource_id, dict):
+            resource_id = resource_id.get('Id')
         if not resource_id:
             raise errors.NullResource(
                 'image or container param is undefined'
             )
-        if isinstance(resource_id, dict):
-            resource_id = resource_id.get('Id')
         return f(self, resource_id, *args, **kwargs)
     return wrapped