dbus -- incomplete fix for CVE-2014-3636 part A

Simon McVittie reports:

The patch issued by the D-Bus maintainers for CVE-2014-3636
was based on incorrect reasoning, and does not fully prevent
the attack described as “CVE-2014-3636 part A”, which is
repeated below. Preventing that attack requires raising the
system dbus-daemon’s RLIMIT_NOFILE (ulimit -n) to a higher
value. CVE-2014-7824 has been allocated for this
vulnerability.