Fix some comments in a backporting review session

* add i18n support to some exception messages
  * remove the return value of DecayingTimer.start()

Relates to review: I898a236a384b3466147026abc7a1ee21801e8ca1

Change-Id: I7adf5478732f1f46db1009b059b66ff8af6ecdc3

oslo/messaging/_drivers/amqpdriver.py

@@ -25,6 +25,7 @@ from oslo import messaging
 from oslo.messaging._drivers import amqp as rpc_amqp
 from oslo.messaging._drivers import base
 from oslo.messaging._drivers import common as rpc_common
+from oslo.messaging._i18n import _
 from oslo.messaging._i18n import _LI
 
 LOG = logging.getLogger(__name__)
@@ -204,7 +205,7 @@ class ReplyWaiter(object):
     @staticmethod
     def _raise_timeout_exception(msg_id):
         raise messaging.MessagingTimeout(
-            'Timed out waiting for a reply to message ID %s' % msg_id)
+            _('Timed out waiting for a reply to message ID %s.') % msg_id)
 
     def _process_reply(self, data):
         result = None
@@ -268,7 +269,8 @@ class ReplyWaiter(object):
         # have the first thread take responsibility for passing replies not
         # intended for itself to the appropriate thread.
         #
-        timer = rpc_common.DecayingTimer(duration=timeout).start()
+        timer = rpc_common.DecayingTimer(duration=timeout)
+        timer.start()
         final_reply = None
         while True:
             if self.conn_lock.acquire(False):

oslo/messaging/_drivers/common.py

@@ -346,14 +346,13 @@ class DecayingTimer(object):
     def start(self):
         if self._duration is not None:
             self._ends_at = time.time() + max(0, self._duration)
-        return self
 
     def check_return(self, timeout_callback, *args, **kwargs):
         if self._duration is None:
             return None
         if self._ends_at is None:
-            raise RuntimeError("Can not check/return a timeout from a timer"
-                               " that has not been started")
+            raise RuntimeError(_("Can not check/return a timeout from a timer"
+                               " that has not been started."))
 
         maximum = kwargs.pop('maximum', None)
         left = self._ends_at - time.time()

oslo/messaging/_drivers/impl_qpid.py

@@ -642,7 +642,8 @@ class Connection(object):
     def iterconsume(self, limit=None, timeout=None):
         """Return an iterator that will consume from all queues/consumers."""
 
-        timer = rpc_common.DecayingTimer(duration=timeout).start()
+        timer = rpc_common.DecayingTimer(duration=timeout)
+        timer.start()
 
         def _raise_timeout(exc):
             LOG.debug('Timed out waiting for RPC response: %s', exc)

oslo/messaging/_drivers/impl_rabbit.py

@@ -695,7 +695,8 @@ class Connection(object):
     def iterconsume(self, limit=None, timeout=None):
         """Return an iterator that will consume from all queues/consumers."""
 
-        timer = rpc_common.DecayingTimer(duration=timeout).start()
+        timer = rpc_common.DecayingTimer(duration=timeout)
+        timer.start()
 
         def _raise_timeout(exc):
             LOG.debug('Timed out waiting for RPC response: %s', exc)