We used to prefix 'rbd:' to volume names, this is not necessary.

Qemu takes RBD devices in this way, like: qemu -drive rbd:pool/image

When attaching a network disk like RBD to a guest we however do not use this prefix.

Currently you can't map a RBD volume name directly to a domain without removing the prefix.
Signed-off-by: NWido den Hollander <wido@widodh.nl>