LU-7334 lov: Cleanup lov_stripe proc files

LU-7334 lov: Cleanup lov_stripe proc files

Make lov_stripe* proc files read only. Writing to
these proc files no longer has any impact.

Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Change-Id: I5adfbbe529208efef760df22c849e3684a34e187
Reviewed-on: http://review.whamcloud.com/20465
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Tested-by: Jenkins
Reviewed-by: Emoly Liu <emoly.liu@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>