Parameterize value `enabled` for cloudwatch-api

Reason: Heat CloudWatch API has been removed from
openstack Queens and above.
Stacklight team have fired Alert about heat cloudwatch but
its a false positive since in recent heat this cloudwatch
is not longer present.

Change-Id: Id540c386f87279d4601b13510b4a548e0f20721f
Related-Prod: PROD-25742 (PROD:25742)
(cherry picked from commit 50676628308afb545d180b5c237b9e9540a0ea85)
5 files changed