Bug 585 : change charm model_name to ns_id and adding index to...

Bug 585 : change charm model_name to ns_id and adding index to application_name to ensure it is unique.
Bug 602 ensure terminating is set in a sooner stage

Change-Id: If1633d7a0a8d39ceabd8bc7a16a9452bf8e80684
Signed-off-by: tierno <alfonso.tiernosepulveda@telefonica.com>