Retry on received == required_responses in DCRP.on_read_timeout

Fixes PYTHON-55

CHANGELOG.rst

@@ -10,6 +10,8 @@ Bug Fixes
   closing excess connections
 * Avoid handling a node coming up multiple times due to a reconnection attempt
   succeeding close to the same time that an UP notification is pushed
+* Correctly retry when received_responses == required_responses in
+  DowngradingConsistencyRetryPolicy.on_read_timeout() (PYTHON-55)
 
 1.1.1
 =====

cassandra/policies.py

@@ -772,7 +772,7 @@ class DowngradingConsistencyRetryPolicy(RetryPolicy):
                         received_responses, data_retrieved, retry_num):
         if retry_num != 0:
             return (self.RETHROW, None)
-        elif received_responses < required_responses:
+        elif received_responses <= required_responses:
             return self._pick_consistency(received_responses)
         elif not data_retrieved:
             return (self.RETRY, consistency)