Allow system apps to write paranoid properties

ParanoidPreferences will use this further in order to avoid root commands

patch set 2: actually working code

Change-Id: If1dcdd67699c64ba5cf428a6ff1e03b46e03a243

Conflicts:
	include/private/android_filesystem_config.h
Merge branch 'jb2' of github.com:CarbonDev/android_system_core into jb2pa
Merge branch 'jb2' of github.com:CarbonDev/android_system_core into jb2pa
Merge branch 'jb2' of github.com:CarbonDev/android_system_core into jb2pa