Revert "location: Allow user to disable GPS"

This reverts commit 5d05b669024b7115fc9b6e128961655c5d105d34.

Had a long discussion with Bastien Nocera and Allan Day on IRC about
this and in the end we decided to go with the simple on/off controls for
now.

Conflicts:
	js/ui/status/location.js

https://bugzilla.gnome.org/show_bug.cgi?id=723684