Schedule to write package restrictions.

In PackageManagerService, for prefered activities,
persistent preferred activities and cross-profile intent filters:
schedule a write to package restrictions instead of writing the file directly.

Also, do not write all settings when writing package restrictions is enough.

BUG: 17996284

Change-Id: Ic732954f8a66d3aa1f0ca85a10fba290b14e68f4