staging: lustre: set downis to 1 if there's no NI for remote net

lnet_route_t::lr_downis is marked as zero even if there is no NI to
target network, this is wrong and breaks logic of ARF. This patch
fixes this problem.
Signed-off-by: Liang Zhen <liang.zhen@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6060
Reviewed-on: http://review.whamcloud.com/13417Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lnet/lnet/router.c

@@ -718,6 +718,13 @@ lnet_parse_rc_info(lnet_rc_data_t *rcd)
 			rte->lr_downis = 0;
 			continue;
 		}
+		/**
+		 * if @down is zero and this route is single-hop, it means
+		 * we can't find NI for target network
+		 */
+		if (!down && rte->lr_hops == 1)
+			down = 1;
+
 		rte->lr_downis = down;
 	}
 }