LU-6261 gnilnd: Hold shared MDD for gnilnd.

LU-6261 gnilnd: Hold shared MDD for gnilnd.

Creating and destroying shared MDDs can cause OS noise. This affects
benchmarks that are sensitive to OS noise like fwq.
Allocate and register some memory so that we always have a shared MDD
available.
Moved kgnilnd_check_kgni_version() into gnilnd.c to simplify
gemini/aries headers.

Signed-off-by: Chris Horn <hornc@cray.com>
Change-Id: Ibc1f4b9a44035c6fb25e88d30552136486c260d6
Reviewed-on: http://review.whamcloud.com/15436
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: James Shimek <jshimek@cray.com>
Reviewed-by: Doug Oucharek <doug.s.oucharek@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>