Revert "Prevent native_init from starting TrafficController"

We are ready to remove traffic controller from netd, so
TrafficController::start() should be called from the system server.

This reverts commit c2984fdca83de11a6a4990576aab1596ef94909b.

Test: atest FrameworksNetTests FrameworksNetIntegrationTests
CtsNetTestCases:android.net.TrafficStatsTest NetworkUsageStatsTest
CtsHostsideNetworkTests

Change-Id: Ic324ad0c064271977ab35d7f55badee00098e196
2 files changed