LU-7421 utils: getparam_display() should reset popt

LU-7421 utils: getparam_display() should reset popt

otherwise it's randomly set leading to wrong output for
lctl get_param. this may break testing.

Change-Id: Ice1ab3ce2ba09a3c6bf6843ff4381ccb73483e42
Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-on: http://review.whamcloud.com/17135
Tested-by: Jenkins
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>