External dependencies update -- dbus-glib & dbus-python

["Elijah Newren" <newren gmail com>]

As reported at http://bugzilla.gnome.org/show_bug.cgi?id=362161,
dbus-glib and dbus-python 0.70 will not build in a clean prefix so
they don't make sense as our depended upon versions of external
dependencies.  So I bumped both to 0.71 at
http://live.gnome.org/TwoPointSeventeen/ExternalDependencies (which
was the recommended version of each anyway) as those versions will
actually build.  :-)