LU-8436 nodemap: MGS local MGC should not get_config

LU-8436 nodemap: MGS local MGC should not get_config

An MGC that is co-located with an MGS does not need to pull the
nodemap config as the MGS will manage it directly. Having the MGC
pull the config could lead to a race condition where new config
changes are overwritten by the old config.

Signed-off-by: Kit Westneat <kit.westneat@gmail.com>
Change-Id: Ief62f44dd3ef75abb704edee0e55f7f1b1334e42
Reviewed-on: http://review.whamcloud.com/21500
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>