Not all preinstalled apps should have access to background
networks or restricted networks. But we give them all network
access permissions currently, it's not a good design. So we
shall limit preinstalled apps permissions, they should just
request the appropriate permission for their use case from
the network permissions.
Bug:19610688
Test: runtest frameworks-net
Change-Id: I184ae3197208c979847ca134c8f01b32528badf1
c7a3a56e57