dlm: fix dlm_recover_members refcount on error

[ Upstream commit 200b977e ]

If dlm_recover_members() fails we don't drop the references of the
previous created root_list that holds and keep all rsbs alive during the
recovery. It might be not an unlikely event because ping_members() could
run into an -EINTR if another recovery progress was triggered again.

Fixes: 3a747f4a ("dlm: move rsb root_list to ls_recover() stack")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>