The virtlockd daemon will maintain locks on behalf of libvirtd.
There are two reasons for it to be separate

 - Avoid risk of other libvirtd threads accidentally
   releasing fcntl() locks by opening + closing a file
   that is locked
 - Ensure locks can be preserved across libvirtd restarts.
   virtlockd will need to be able to re-exec itself while
   maintaining locks. This is simpler to achieve if its
   sole job is maintaining locks
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>