LU-14806 o2iblnd: clear fatal error on successful failover

LU-14806 o2iblnd: clear fatal error on successful failover

In IB bonding configuration link down event causes fatal error
flag to be set on the bonded interface so it is not selected by
LNet for tx, e.g. when just one of the two cables is pulled.
This change allows for the interface status to be restored on
successful failover.

Lustre-change: https://review.whamcloud.com/44139
Lustre-commit: 4668283cd13079dd6d86482704aef593f5c01dff

Test-Parameters: testlist=sanity-lnet
Signed-off-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Change-Id: Ifd55b141e73d01a187c02ede3f021f0eab18e0bb
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/44933
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>