Add attach/detach cloud volume errors
Add attach/detach cloud volume errors

This adds two new error types that need to be thrown when cloud volume
attach/detach fails.

Signed-off-by: Gregor Berginc <e4e005392409b3839684d772373f610aa5cbddd3@gmail.com>

aljesusg/manageiq-gems-pending,rsevilla87/manageiq-gems-pending,rsevilla87/manageiq-gems-pending,aljesusg/manageiq-gems-pending