Adding alarm delete coverage of API

lib/fog/rackspace/monitoring.rb

@@ -64,6 +64,7 @@ module Fog
       request      :update_alarm
 
       request      :delete_agent_token
+      request      :delete_alarm
       request      :delete_check
       request      :delete_entity
 

lib/fog/rackspace/requests/monitoring/delete_alarm.rb

@@ -0,0 +1,18 @@
+module Fog
+  module Rackspace
+    class Monitoring
+      class Real
+
+        def delete_alarm(entity_id, alarm_id)
+          request(
+            :expects  => [204],
+            :method   => 'DELETE',
+            :path     => "entities/#{entity_id}/alarms/#{alarm_id}"
+          )
+        end
+
+      end
+    end
+  end
+end
+