ITS#9598 Do not track olcIncomingConnections in lloadd/test007

ITS#9598 Do not track olcIncomingConnections in lloadd/test007

Some values we export in cn=monitor are not managed in a single place,
instead, a task exists that gathers a snapshot of the lloadd state and
stores it for monitor consumption. This exposes a race between the test
reading it out and lloadd updating this cached copy. While we still have
to rely on a shell, rather than being intelligent about whether or not
we should emit a readout into search.out or wait and try again (which is
what test004-monitor does), just filter this attribute out.