LU-6025 lctl: remove bad error checking from nodemap_cmd()

LU-6025 lctl: remove bad error checking from nodemap_cmd()

There was some error checking that didn't really make sense in
nodemap_cmd() and was causing false errors. memcpy() doesn't have an
error condition, so there's no need to check it.

Signed-off-by: Kit Westneat <kit.westneat@gmail.com>
Change-Id: I58225f8ebb1d8dc0941534503f939b213d57c27f
Reviewed-on: http://review.whamcloud.com/13191
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>