CP-5830: Productise removal of lvm2-master-mode.patch

Removed the --master switch from lvm commands. We now use two separate lvm
conf files for master and slave nodes. Appropriate conf file is chosen
through an environment variable.

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

GitHub: closes #29 on xapi-project/sm