LU-13025 lnet: pick healthiest peer net

LU-13025 lnet: pick healthiest peer net

When iterating over the peer nets, select the healthiest one.
Node might be able to reach a peer over multiple nets, and therefore
the health of these peer nets must be considered.

Test-parameters: trivial

Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I155888dca358627fcb63c2ed0e51114bc49a9ff1
Reviewed-on: https://review.whamcloud.com/36912
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>