LU-7199 nodemap: assign nodemap to export before connecting

LU-7199 nodemap: assign nodemap to export before connecting

This patch moves the nodemap assignment to be before the connection
is active, and the nodemap deassignemnt to be after the connection
is made inactive. It also checks for null nodemaps and returns
-EACCES if the nodemap is not set in order to avoid a kernel panic.

Signed-off-by: Kit Westneat <kit.westneat@gmail.com>
Change-Id: Id4dd02cf5b4208bda6d6f17aed6adb13b18c7731
Reviewed-on: http://review.whamcloud.com/16802
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>