Downgrade log when attach interface can't find resources

Downgrade the log when a resource (e.g. instance is deleted concurrently)
can't be found, no need to LOG.exception because an exception
is already raised and no need to log again.

Change-Id: I260e89c8deab11bc9707abbbbc7bb9a4f88640e3
Closes-Bug: #1322410
[EC2]Correct the return status of attaching volume

The EC2 API return volume's status as 'detached' in response when
attaching a volume.
It should be 'attaching' according to EC2's API docs, so we should convert
the volume_status or volume attach_status to ec2 volume attachment status.
The situation is similar in detaching volume.

Change-Id: Ifacf0ffcab49394def948d428c4c4c13d08152f0
Closes-bug: #1280572
XenAPI: Tolerate multiple coalesces

VHD coalescing might coalesce more than one VDI while waiting
and might coalesce the 'grandparent' before the parent.  Wait
for the parent to be any of the original tree instead of just
the original parent.

Closes bug: 1317792

Change-Id: I82c4db0e8a36c41a86adf4bd32304a4bfdabebbf
Reverse order of cinder.detach() and bdm.delete()

The user experience for detaching a volume is better if the bdm
is destroyed as soon as the driver has detached the volume instead
of waiting until after we have updated cinder.

Change-Id: I6f3de25f7737db270af4ba41d7451ae95f3950f5
Closes-Bug: #1309154
Merge "XenAPI: Tolerate multiple coalesces"
Merge "Reverse order of cinder.detach() and bdm.delete()"
Merge "[EC2]Correct the return status of attaching volume"
Merge "Downgrade log when attach interface can't find resources"