Raise exception when error_deleting

Tempest checks a volume delete by waiting for NotFound(404) on
show_volume(). Sometime a volume delete fails and the volume status
becomes error_deleting which means the delete is failed.
So Tempest doesn't need to wait anymore. This patch makes the check
raise an exception instead of waiting.

Closes-Bug: #1686429

Change-Id: I17a986be2eb05ef9b177d5248de02a3336f7d4bb
2 files changed