Adding keystone notification listener support

Notification listener processes only keystone project delete events.
It uses keystone project id to identify if related barbican resources are there
and deletes that project related barbican resources.

10/07/2014: Keep resolving rebase conflicts as this change is pending for a while.
Modified listener transaction logic as per related recent change in barbican.
Fixed missing patcher stop in few places which was causing failure in new tests.

Implements: blueprint consume-keystone-events

Change-Id: Iba7d50eb222edd43352ef82f629df2b3187c76ec