Revert "dbus: 1.8.20 -> 1.10.8"

This reverts commit d088e062.

The D-Bus update breaks logind and polkit.

(cherry picked from commit 2e06e5eb)

Hydra had rebuilt this on staging, fixing many test problems.
There were also phonon changes in these rebuilds, but the amount of
binaries affected by them is relatively low and I'm not yet fully
convinced of their stability.