LU-6025 utils: reset optind before calls to getopt_long()

LU-6025 utils: reset optind before calls to getopt_long()

The nodemap commands in lctl were not properly resetting optind
between calls to getopt_long(). This patch sets optind to 0 before
calling any subcommands.

Signed-off-by: Kit Westneat <kit.westneat@gmail.com>
Change-Id: I14a1f34000c678799298dae3c248c839a1f32d52
Reviewed-on: http://review.whamcloud.com/13063
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Jenkins
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>