Audio: Fix abnormal keytone playback during silent mode changing

Change-Id: Icfc4003c9756b3c33578c137e59dc4a2b4f25647
Author: Chenyang Du <chenyang.du@intel.com>
Signed-off-by: Ertao Zhao <ertaox.zhao@intel.com>
Signed-off-by: Shuo Gao <shuo.gao@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
Signed-off-by: Jack Ren <jack.ren@intel.com>
Author-tracking-BZ: 19084 4898
PackageManager: Let system-defined permissions take precedence over settings

If a permission was already present in the device's settings due to having
no prior system definition, and the system tried to take it over
(after a version upgrade, for example), it'd fail, since the saved
value would clobber the one previously read from the permissions XML.

This breaks system-behavior changes (gid grants, in particular) unless
the user performs a factory reset after upgrading, which isn't acceptable.

Change-Id: If2e44110f6db735ad29cdf1086e814bd1299e290