Verify shill creates IPConfig objects for IPv6

As a part of the network_Ipv6SimpleNegotiation test, verify that
the temporary IPv6 address is available in the list of IPConfigs
in the assocaited Device object in shill.

CQ-DEPEND=CL:197304
BUG=chromium:365883
TEST=Run this test

Change-Id: I42e4395a706805fa8612c934cb338aede7262e04
Reviewed-on: https://chromium-review.googlesource.com/197394
Reviewed-by: mukesh agrawal <quiche@chromium.org>
Tested-by: Paul Stewart <pstew@chromium.org>
Commit-Queue: Paul Stewart <pstew@chromium.org>
2 files changed