Revert "Settings: add built-in superuser"

This reverts commit 17d7169fa5b8f3acf02679258a19f3bf737b4484.
Start SuperSU from Development Settings

orig from SimpleAOSP
https://github.com/SimpleAOSP-Lollipop/platform_packages_apps_Settings/commit/10bdc1128067961810eb008a527441fb8e7a56b3