FIX: Support metadata changes rollback

FIX: Support metadata changes rollback

Function reshape_super() guards metadata changes.
It is used to apply changes rollback in error case also.
As change (apply and rollback) can be not bi-directional reshape_super()
has to know if current action is metadata change that should be guarded
using metadata restrictions, or this is metadata rollback change
executed due to error occurrence.

In second case change has to be unconditional.

Signed-off-by: Adam Kwolek <adam.kwolek@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>