Have IpManager track L2-L4 signaling traffic required for IP connectivity.

Test: as follows
    - built and flashed
    - observed logcat
    - observed "dumpsys wifi ipmanager"
    - runtest BlockingSocketReaderTest passes
    - runtest ConnectivityPacketSummaryTest passes
Bug: 21859053
Bug: 26101306
Bug: 31742572
Bug: 31707128
Bug: 33531488

Change-Id: Ibecaf809dcc1813924b25749e8ba8eb2d4bdf114