Changed AsyncWatcher class to use a new feature.

sjrpc/core/async.py

@@ -74,7 +74,7 @@ class AsyncWatcher(object):
            >>>     process(msg)
         '''
         responses = []
-        while self._expected_responses:
+        while self.remains:
             try:
                 dt, response = self._get_in_queue(timeout=timeout)
             except Empty: