LU-5030 utils: add -R parameter to lctl get_param

LU-5030 utils: add -R parameter to lctl get_param

To allow printing all parameters under a specified directory.
This is needed to replace hard-coded /proc pathnames in sanity-sec.sh
test_24, but would also be useful for normal usage.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Emoly Liu <emoly.liu@intel.com>
Change-Id: I4391afce06fd63a87f556f7b95bd0cb2883ebbe5
Reviewed-on: http://review.whamcloud.com/17081
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Frank Zago <fzago@cray.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>