Re-land "[shill] Add hardware address to Device objects."

Forgot some headers...

BUG=chromium-os:17744
TEST=unit

This reverts commit 0fda552b0fec3498403336acb9e89dd7799cac74.

Change-Id: I1cd05e47d29bc7ea2a065cabf1d81dd37f74c0f8
Reviewed-on: http://gerrit.chromium.org/gerrit/6270
Reviewed-by: Chris Masone <cmasone@chromium.org>
Tested-by: Chris Masone <cmasone@chromium.org>
diff --git a/mock_device.h b/mock_device.h
index 2147bbc..f1205cf 100644
--- a/mock_device.h
+++ b/mock_device.h
@@ -23,6 +23,7 @@
              EventDispatcher *dispatcher,
              Manager *manager,
              const std::string &link_name,
+             const std::string &address,
              int interface_index);
   virtual ~MockDevice();