Add delete support for volume type encryption

This modification adds delete support to the volume type
encryption API extension.  The delete operation is not
permitted when the encrypted volume type is in use by an
existing volume.

Change-Id: Ic490fd3f0f1b1282cd24c65886c92beb88d30560
Implements: blueprint encrypt-cinder-volumes
GPFS Driver missing clone depth limit for snapshots

GPFS driver is fixed to handle snapshot clones correctly. Previously,
these were allowed to grow without respecting limit defined in config
flag gpfs_max_clone_depth.  This change adds the depth check operation
in create_snapshot.

To ensure that all clone files are cleaned up, the delete_snapshot
method now marks snapshots to be deleted with ts file extension
and attempts to delete the snapshot.  If the snapshot cannot be
deleted because it has clone children, it will be deleted when the
child is deleted.

Closes-Bug: #1227366

Change-Id: I4fb2a720b55dbe033159e6fb341f6e2f1508776e
Add sg_scan filter to rootwrap

The sg_scan command was missing from rootwrap.

Change-Id: I549b51e30c53eb588b02dc0892c8e32d2c66c6bb
Closes-Bug: #1225102
Merge "Add sg_scan filter to rootwrap"
Merge "Add delete support for volume type encryption"
Merge "GPFS Driver missing clone depth limit for snapshots"