Handle InstanceInvalidState of soft_delete

Since commit 99c51e34230394cadf0b82e364ea10c38e193979, instance
is not able to be soft_deleted if instance has never been active.
But there are circumstances when instance fails on initial build.
Thus if we set reclaim_instance_interval in nova.conf, we cannot
delete such instances in any way.

This patch fixes this by handling InstanceInvalidState exception
when try to soft_delete instance. The delete() function is called
for instance which has never been active.

Bug 1202158

Change-Id: I7d0d9414d7436e56b6a3e5861ee3c2f02473df2b
Merge "Handle InstanceInvalidState of soft_delete"