Define UPOWER_ENABLE_DEPRECATED

https://git.gnome.org/browse/gnome-session/commit/gnome-session/gsm-logout-dialog.c?h=gnome-3-8&id=9646cc98b6a204f08c1ed06d75404610251e30e7
Merge pull request #2 from leigh123linux/patch-2

Define UPOWER_ENABLE_DEPRECATED