LU-7403 obd: const correct md_set_lock_data()

LU-7403 obd: const correct md_set_lock_data()

Change the __u64 *cookie parameter of md_set_lock_data() to const
struct lustre_handle *lockh.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: Ie6de252a10c532ee395e407ad2aff258773478a8
Reviewed-on: http://review.whamcloud.com/17072
Reviewed-by: Frank Zago <fzago@cray.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>