Add test case: delete snapshot when driver not initialized
Add test case: delete snapshot when driver not initialized

This patch add test case: when deleting snapshot, volume driver is
not ready, the snapshot status will be set 'error_deleting'.

Change-Id: I71b6071026b3b60c5fb3a0d72149f2f3c529af68

openstack/cinder,mahak/cinder,mahak/cinder,openstack/cinder