pulseaudio: add x11 to PACKAGECONFIG as appropriate

Signed-off-by: Christopher Larson <kergoth@gmail.com>
pulseaudio: use PACKAGECONFIG to control rdep on console-kit

We use PACKAGECONFIG to control the emission of the console-kit module
package, and installation of that module, but we were using DISTRO_FEATURES to
control the pulseaudio-server dependency on the console-kit module. This
breaks the case where DISTRO_FEATURES contains x11 but the pulseaudio
PACKAGECONFIG does not.

Signed-off-by: Christopher Larson <kergoth@gmail.com>