build: Remove UPower 0.9 support

The 1.0 API has been current for 4 years, so we shouldn't need to
support the old 0.9 API. mutter, gnome-shell, gnome-control-center and
gnome-settings-daemon all support the newer 1.0 API.

https://bugzilla.gnome.org/show_bug.cgi?id=787806