Using LOG.warning replace LOG.warn


*Python 3 deprecated the logger.warn method, see:
*https://docs.python.org/3/library/logging.html#logging.warning
*so we prefer to use warning to avoid DeprecationWarning.

Change-Id: I07ee9c97c3548c965aaf83d34b37b23e9baba584
diff --git a/scenario/test_ceilometer_alarm.py b/scenario/test_ceilometer_alarm.py
index e0523aa..aa29861 100644
--- a/scenario/test_ceilometer_alarm.py
+++ b/scenario/test_ceilometer_alarm.py
@@ -30,8 +30,8 @@
         stack = self.client.stacks.get(stack_identifier)
         actual = self._stack_output(stack, 'asg_size')
         if actual != expected:
-            LOG.warn('check_instance_count exp:%d, act:%s' % (expected,
-                                                              actual))
+            LOG.warning('check_instance_count exp:%d, act:%s' % (expected,
+                                                                 actual))
         return actual == expected
 
     def test_alarm(self):