[ofa-general] lock dependency in ib_user_mad

[Roland Dreier]

 > Did you try multiple OpenSM instances on the same port ? My memory is a
 > little fuzzy on this but I think that there used to be some user_mad
 > error returned for this rather than it blocking. Was that behavior
 > preserved ?

There should be no changes in behavior other than fixes like not
deadlocking in some cases.  If I run opensm twice I get

    Error from osm_opensm_bind (0x2A)
    Perhaps another instance of OpenSM is already running
    Exiting SM

with the new code.

 - R.