Bug#874586: actually, it's Wayland that's the problem

[Christopher Cramer]

After some further investigation, I have discovered that the problem
is apparently caused by GDM now defaulting to Wayland, which has no
accessibility support. My complaint about the lack of an error message
still stands.

This bug is, perhaps, a duplicate of 648292.

To work around this, uncomment "WaylandEnable=false" in
/etc/gdm3/daemon.conf.