[moblab] Fix broken dut_check checkfile
dut_check relied on commands (arp, fping) which are not installed
on moblab. Rewriting this check to use ip neighbors, ping instead.
BUG=chromium:732598
TEST=Local moblab device, unplug and replug a moblab's lone
DUT to verify the error correctly hides and shows.
Change-Id: I897de17c69b0b4835c65da563b8386c571032217
Reviewed-on: https://chromium-review.googlesource.com/957885
Commit-Ready: Matt Mallett <mattmallett@chromium.org>
Tested-by: Matt Mallett <mattmallett@chromium.org>
Reviewed-by: Keith Haddow <haddowk@chromium.org>
3 files changed
