[2/2] Framework/base: Configure headset hook

Whether or not to allo headset hook to launch voice commands

Useful with headset control programs

PS3: Dont use getIntForUser directly. It breaks
PS5: Whitespce
PS6: Rebase

Change-Id: Ifc24407b87a469a4baadad098895564f7f9aecb8
Merge remote-tracking branch 'omni/android-4.4' into omni-4.4