Stop using shared DUN APN when tethering stops.

Backported from master, including a bug fix and a cdma enhancement.

Even if other people are sharing the connection (ie, carrier wants
default and tethered traffic on the same APN) stop using a carrier-
described APN when the tethering stops.

bug:5972599
Change-Id: I25e4831855e6b62c0c3ab3a6f4d4846aaee6ac50
1 file changed
tree: 976c18d3c3dcc8d2aba3fc2ecaf2fa079d80934c
  1. core/
  2. services/