LU-14545 tests: erase failover.node parameter

LU-14545 tests: erase failover.node parameter

On the "failover pair" Lustre configuration, like
    mds1_HOST=host1
    mds2_HOST=host2
    mds1failover_HOST=host2
    mds2failover_HOST=host1
fs2mdsdev can not be mounted on mds1_HOST because of fs2mdsdev
has failover.node=<mds1_HOST>. Mount fails as:
    Denying initial registration attempt from nid <mds1_HOST>@tcp,
    specified as failover.

Patch erases fs2mdsdev failover.node parameter.

Test-Parameters: trivial testlist=conf-sanity envdefinitions=ONLY=32
Signed-off-by: Elena Gryaznova <elena.gryaznova@hpe.com>
HPE-bug-id: LUS-9821
Reviewed-by: Vladimir Saveliev <vladimir.saveliev@hpe.com>
Reviewed-by: Alexander Zarochentsev <alexander.zarochentsev@hpe.com>
Change-Id: Id96cb12704fc79f32ea998702bb457d2f683a7c8
Reviewed-on: https://review.whamcloud.com/42131
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Vladimir Saveliev <c17830@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>