Fix dashboard creation during grafana.client state

During the execution of pipeline we'll get the following error:
"Failed to create dashboard nginx, response={u'status': u'not-found', u'message': u'Dashboard not found'}"
This commit refactoring the logic of execution of grafana.client state.
It is executing salt-call on each mon node one by one via salt batch.

Change-Id: Ie29ce6b01943d1f783b88a3c7ae64a106a0424a5
1 file changed