Fixes ceph volume restore to larger image than source

If a backup is restored to a volume that is bigger than the
backup itself, which could be the case if --volume-id is
supplied, we need the option to set extraneous extents to zero
i.e. set extents after those from the backup to zero.

Change-Id: I3c226b9e7429371f6cd9b9bd81071ff765712975
Fixes: bug 1225126
Do not use qemu-img --backing-chain or --output=json

Initial code for GlusterFS snapshot support in Havana
used qemu-img arguments which are too new to run in many
environments.  Run qemu-img using only arguments which
will exist on older platforms.

Partial-Bug: #1224030
Change-Id: I5155dac492da67a951ede978c2c46a54c239eb04
Merge "Fixes ceph volume restore to larger image than source"