LU-13782 lnet: Have LNet routers monitor the ni_fatal flag

LU-13782 lnet: Have LNet routers monitor the ni_fatal flag

Have the LNet monitor thread on LNet routers check the
ni_fatal_error_on flag to set local NI status appropriately. When
this results in a status change, perform a discovery push to all
peers. This allows peers to update their route status appropriately.

Test-Parameters: trivial
HPE-bug-id: LUS-9068
Signed-off-by: Chris Horn <chris.horn@hpe.com>
Change-Id: Ic4f8f33c6377f4b95f6ab95f9714414c6b9ab5e6
Reviewed-on: https://review.whamcloud.com/39353
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>