CP-5831: Productise removal of lvm2-lvchange-idempotent.patch

Part of changes required to remove lvm2-lvchange-idempotent.patch. LVM throws
an error if an LV that is already RO is set to RO again or an RW lv is set to
RW. Added additional check on XS side to check LV status before changing access
permissions.

Signed-off-by: Chandrika Srinivasan <chandrika.srinivasan@citrix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@citrix.com>

GitHub: closes #26 on xapi-project/sm