allow cloning of any volume to any volume with same parent ID

allow cloning of any volume to any volume with same parent ID

remove checks to disallow cloning of ro volumes to rw volumes,
which allows cloning of any volume within the same parent ID
grouping, including allowing destruction of newer version of the
volumes.

Reviewed-on: http://gerrit.openafs.org/5049
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit 83c41c69411ece7ac1dd0a7b15d4ee9746edcf23)

Change-Id: Idc2575538811d278fb65be46cfc0cd4d24d90f5d
Reviewed-on: http://gerrit.openafs.org/5725
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Derrick Brashear <shadow@dementix.org>