GPFS driver does not delete .snap file in case of reset-state + force-delete

[Margarita Shakhova]

1. Create a volume as a clone (either clone a volume created from image or use glance image-volume cache).
2. Attach the volume to a VM.
3. Reset-state this volume ('available' + 'detached').
4. Delete the volume.

Expected behavior: volume deleted and all corresponding files removed from the GPFS.
Actual behavior: volume deleted from cinder, and file volume-<volume uuid>.snap remains in the FS.

From cinder-volume logs:

CMD "sudo cinder-rootwrap /etc/cinder/rootwrap.conf rm -f /mnt/gpfs0/cinder/volume-a5e4d43a-ca3a-4ac3-93fe-0a542ef8f10b" returned: 0

CMD "sudo cinder-rootwrap /etc/cinder/rootwrap.conf rm -f /mnt/gpfs0/cinder/volume-a5e4d43a-ca3a-4ac3-93fe-0a542ef8f10b.snap" returned: 1