DevSettings: Fix the root-access toggle in eng builds

It was being unconditionally removed, put it back

Change-Id: I8eecab7353c59b224d917cc1710124f57656cf47
Merge "DevSettings: Fix the root-access toggle in eng builds" into cm-10.2
Merge branch 'cm-10.2' of git://github.com/CyanogenMod/android_packages_apps_Settings into cd-4.3