shill: Parse dhcpcd Event signal properties.

BUG=chromium-os:16126
TEST=unit test

Change-Id: Idafd3cebc015a5f900fd589c27dfcd1b405da7ef
Reviewed-on: http://gerrit.chromium.org/gerrit/2126
Reviewed-by: Chris Masone <cmasone@chromium.org>
Tested-by: Darin Petkov <petkov@chromium.org>
8 files changed