Notify with string representation of alarm reason

Fixes bug 1227668

Ensure string representation of alarm reason is passed to the
alarm notifier over RPC (as opposed to a gettextutils.Message
instance).

Change-Id: I6a840789f83068ee5721cb139b06cf0071240152

ceilometer/alarm/rpc.py

@@ -44,5 +44,5 @@ def notify(self, alarm, previous, reason):
             'alarm_id': alarm.alarm_id,
             'previous': previous,
             'current': alarm.state,
-            'reason': reason})
+            'reason': unicode(reason)})
         self.cast(context.get_admin_context(), msg)

tests/alarm/test_rpc.py

@@ -91,3 +91,8 @@ def test_notify_alarm(self):
                              self.alarms[i].state)
             self.assertEqual(self.notified[i][1]["args"]["data"]["reason"],
                              "what? %d" % i)
+
+    def test_notify_non_string_reason(self):
+        self.notifier.notify(self.alarms[0], 'ok', 42)
+        reason = self.notified[0][1]['args']['data']['reason']
+        self.assertTrue(isinstance(reason, basestring))