LU-12422 lnet: discovery off route state update

LU-12422 lnet: discovery off route state update

When discovery is off rely on the discovery ping response
only, rather than the internal peer database to determine
route state. With discovery off the internal peer database
is not updated with all the gateway's interfaces.

Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Signed-off-by: Chris Horn <hornc@cray.com>
Change-Id: If1b5347629ffeb92208097c06d708e1105d27679
Reviewed-on: https://review.whamcloud.com/35199
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Olaf Weber <olaf.weber@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>