Ensure hmget return right data format

The Jenkins is done due to the funtional test[1] in redis backend.

The reason is that we use hmget to get the information but hmget
can't distinguish integer. it returns all value in string format.

This patch did a quick fix to let jenkins work.

[1]: https://github.com/openstack/python-zaqarclient/blob/master/zaqarclient/tests/queues/subscriptions.py#L212

Change-Id: I0dcb50535913457ae1ad705939dcff555c6e1ae8

zaqar/storage/redis/subscriptions.py

@@ -77,7 +77,7 @@ class SubscriptionController(base.Subscription):
                 'id': sid,
                 'source': record[0],
                 'subscriber': record[1],
-                'ttl': record[2],
+                'ttl': int(record[2]),
                 'options': self._unpacker(record[3]),
             }
             marker_next['next'] = sid