Use the global environment to define AWS::CloudWatch::Alarm

This will make it easier for the deployer to define the default
implementation.

Change-Id: If1a8dceb4ad2cade90a56f16dd450e571425c4a6

etc/heat/environment.d/default.yaml

@@ -0,0 +1,3 @@
+
+resource_registry:
+    "AWS::CloudWatch::Alarm": "OS::Heat::CWLiteAlarm"

heat/engine/resources/cloud_watch.py

@@ -132,5 +132,5 @@ class CloudWatchAlarm(resource.Resource):
 
 def resource_mapping():
     return {
-        'AWS::CloudWatch::Alarm': CloudWatchAlarm,
+        'OS::Heat::CWLiteAlarm': CloudWatchAlarm,
     }

heat/tests/common.py

@@ -16,7 +16,12 @@
 import fixtures
 import logging
 import mox
+import os
+import sys
 import testtools
+
+from oslo.config import cfg
+
 import heat.engine.scheduler as scheduler
 
 
@@ -33,3 +38,10 @@ class HeatTestCase(testtools.TestCase):
             scheduler.ENABLE_SLEEP = True
 
         self.addCleanup(enable_sleep)
+
+        mod_dir = os.path.dirname(sys.modules[__name__].__file__)
+        project_dir = os.path.abspath(os.path.join(mod_dir, '../../'))
+        env_dir = os.path.join(project_dir, 'etc', 'heat',
+                               'environment.d')
+
+        cfg.CONF.set_default('environment_dir', env_dir)