dbus: security bump to version 1.8.8

Fixes:
CVE-2014-3635 - Buffer access with incorrect length value
CVE-2014-3636 - Allocation of file descriptors or handles
without limits or throttling
CVE-2014-3637 - Missing release of file descriptor or handle after
effective lifetime
CVE-2014-3638 - Algorithmic complexity
CVE-2014-3639 - Allocation of file descriptors or handles without
limits or throttling

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>