Catch generic exceptions

Catch generic exceptions

When the driver copy_image_to_volume fails it can
at the current time raise more than just CinderException
as its root exception type. This causes rescheduling due
to the blacklisted exception list that is used to determine
if a exception is 'bad enough' to trigger rescheduling or
should the volume creation action just set the volume to
error state.

To avoid the situation where this would cause a rescheduling
we should make sure (for now) that any exception that is
emitted on copying an image to a volume is translated
into a image copy failure and reraised.

Fixes: bug 1224211
Change-Id: Ia4a0a81d9e0967b1e7de07577d77084462304c60