Basic framework for DHCPv6 testing

Perform basic setups and verification for DHCPv6 testing.

BUG=chromium:496361
TEST=Upcoming client test network_Dhcpv6Basic

Change-Id: I6db821a3d036126fa6e3d613457ed231f954304f
Reviewed-on: https://chromium-review.googlesource.com/281181
Reviewed-by: Paul Stewart <pstew@chromium.org>
Tested-by: Zeping Qiu <zqiu@chromium.org>
Commit-Queue: Zeping Qiu <zqiu@chromium.org>
1 file changed