LU-13988 mdt: ASSERTION(!lustre_handle_is_used(&lh->mlh_reg_lh)) failed

LU-13988 mdt: ASSERTION(!lustre_handle_is_used(&lh->mlh_reg_lh)) failed

mdt_brw_enqueue() should clear lock handle on error.

HPE-bug-id: LUS-8740
Change-Id: Ic2201189af6bcb2b1a114a599e138f9c22f3d99d
Signed-off-by: Andriy Skulysh <c17819@cray.com>
Reviewed-by: Alexandr Boyko <c17825@cray.com>
Reviewed-by: Alexander Zarochentsev <c17826@cray.com>
Reviewed-on: https://review.whamcloud.com/40045
Reviewed-by: Alexander Boyko <alexander.boyko@hpe.com>
Reviewed-by: Alexander Zarochentsev <alexander.zarochentsev@hpe.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>