Reland: Change to Shill's IPConfig objects.

Reland: Change to Shill's IPConfig objects.

Before a recent Shill change, Static and Saved IP config properties were stored in toplevel properties with prefixed keys like kStaticIPAddressProperty.
This change makes use of Shill now exposing these properties nested under a StaticIPConfig and SavedIPConfig dictionary.

This also makes the translation between a list of nameservers and a comma-separated string obsolete.

Original Review URL: https://codereview.chromium.org/762243002

BUG=411289
TBR=pneubeck@chromium.org

Committed: https://crrev.com/870dfbecc375b1e0d89594e1f7de5fa7a4e1ea84
Cr-Commit-Position: refs/heads/master@{#306669}

[stevenjb, 2014-12-03 19:57:06]

The CQ bit was checked by stevenjb@chromium.org

[commit-bot: I haz the power, 2014-12-03 19:57:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/778693004/1

[commit-bot: I haz the power, 2014-12-03 20:44:33]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-12-03 20:46:22]

Patchset 1 (id:??) landed as
https://crrev.com/870dfbecc375b1e0d89594e1f7de5fa7a4e1ea84
Cr-Commit-Position: refs/heads/master@{#306669}