LU-11299 lnet: modify lnd notification mechanism

LU-11299 lnet: modify lnd notification mechanism

LND notifies when a peer is up or down. If the LND notifies
LNet that the peer is up and sets the "reset" flag to true
then this indicates to LNet that the LND knows about the health
of the peer and is telling LNet that the peer is fully healthy.
LNet will set the health value of the peer to maximum, otherwise
it will increment the health by one.

If the LND notifies the LNet that the peer is down, LNet will
decrement the health of the peer by sensitivity value configured.

LNet then turns around and rechecks the peer aliveness and if its
dead it'll notify the LND. This code is only used by the socklnd
because it needs to tear down connections. This is in keeping with
the original functionality.

Test-Parameters: forbuildonly
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: Ifa614405fb0c2cd4f6bcb1a2a97e856320eb6cbe
Reviewed-on: https://review.whamcloud.com/33453
Reviewed-by: Olaf Weber <olaf.weber@hpe.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Tested-by: Jenkins