Raise descriptive error for over volume quota

If you attempt to create a new instance booting from an image and you
were over your quota on cinder, the nova manager would see that as an
invalid block device. This raises a more descriptive error message in
the logs.

Closes-bug: #1013417
Change-Id: Ie50b97c31580da7fc38c6891d1f3646b91f8aa10
Merge "Raise descriptive error for over volume quota"