TicketSQL queue-specific CF syntax is CF.Queue.{Name} not CF.{Queue}.{Name}

This bug was introduced by bd2bbef, but only manifests when QUEUE is
passed to RT::Tickets->LimitCustomField.  Such an invocation is never
called in core RT.

    (Cherry picked from RT commit 317565e706e0a78007ddb7b98895210ac3a490a9)