LU-4780 lnet: NI shutdown may loop forever

LU-4780 lnet: NI shutdown may loop forever

lnet_shutdown_lndnis() may enter endless loop if there is a busy NI,
this is injected by LNet SMP improvements. It's fixed in this patch.

Signed-off-by: Liang Zhen <liang.zhen@intel.com>
Change-Id: I612ab9ff15aa40c05d6bd4cfee7cd107715f41b4
Reviewed-on: http://review.whamcloud.com/9706
Tested-by: Jenkins
Reviewed-by: Isaac Huang <he.huang@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Bobi Jam <bobijam@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>