dlm: fix error if active rsb is not hashed

If an active rsb is not hashed anymore and this could occur because we
releases and acquired locks we need to signal the followed code that
the lookup failed. Since the lookup was successful, but it isn't part of
the rsb hash anymore we need to signal it by setting error to -EBADR as
dlm_search_rsb_tree() does it.

Cc: stable@vger.kernel.org
Fixes: 5be323b0 ("dlm: move dlm_search_rsb_tree() out of lock")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>