Direct notification of network interface changes.

Connectivity broadcasts recently changed and are no longer sent for
certain types of network changes.  For example, when stacked network
interfaces change for a mobile network.  To ensure that we pick up
all these details, directly wire the two services together.

Also remove some unused code for split network types.

Bug: 18666753
Change-Id: I0467bd5b330c0e0cb51af2306d821b41ad16337a