Add raise_for_status check to push and pull methods

as underlying exceptions(such as push already in progress) will be hidden in the stream generator otherwise.

Author: bcicen

docker/client.py

@@ -914,6 +914,8 @@ def pull(self, repository, tag=None, stream=False,
         response = self._post(self._url('/images/create'), params=params,
                               headers=headers, stream=stream, timeout=None)
 
+        self._raise_for_status(response)
+
         if stream:
             return self._stream_helper(response)
         else:
@@ -950,6 +952,8 @@ def push(self, repository, tag=None, stream=False,
         else:
             response = self._post_json(u, None, stream=stream, params=params)
 
+        self._raise_for_status(response)
+
         return stream and self._stream_helper(response) \
             or self._result(response)