RA and ocft for sg_persist

sg_psersist is a resource agent that implements SPC-3 Persistent
Reservations (contribution from Evgeny Nifontov).

Customers with an active-passive storage setup using MD-raid1 need
to ensure, that the MD device is only activated on one system at a
time. While this is clearly possible with the existing Raid1 RA,
there is still the possibility that crazy system administrators
assemble such devices manually from the command line, leading to
a complete data-loss as a result...

There exists an implementation of a resource agent around the "sg_persist"
Utility from the sg3_utils package. The sg_persist RA is just based on
the sg3_utils tools. It works as a Master/Slave resource. It registers a
reservation key for devices when the resource starts and holds reservation
when the resource promotes to be a Master. There exist only one Master
in case of the reservation type is 1/3/5/6 and can have multi Masters
in case of the reservation type is 7/8.

Signed-off-by: Evgeny Nifontov
Signed-off-by: Liuhua Wang lwang@suse.com