Add Beacon Loss tests

Observe that DUT marks the current service as "idle" after we
"pull the plug" on the AP.  To do this, we discover what drivers
the AP uses for WiFi and reload them.

BUG=chromium-os:15981  (this CL expresses that bug)
TEST=Run test

Change-Id: I37b5f15658dec410c53e3dc1a5f8f7f1d0f34602
Reviewed-on: http://gerrit.chromium.org/gerrit/1891
Reviewed-by: Sam Leffler <sleffler@chromium.org>
Tested-by: Paul Stewart <pstew@chromium.org>
4 files changed