Leave a labmachine marker after an update comes back from reboot.

This is to ensure we have a way to distinguish lab machines vs machines
with Chromium OS test images without the presence of networking during
possible flakiness as the result of a test.

BUG=chromium-os:34178
TEST=Manual

Change-Id: I8649c5bae44b6201c64e65b10dc63d150daa46e9
Reviewed-on: https://gerrit.chromium.org/gerrit/33657
Tested-by: Chris Sosa <sosa@chromium.org>
Reviewed-by: Simran Basi <sbasi@chromium.org>
Reviewed-by: Scott Zawalski <scottz@chromium.org>
Commit-Ready: Chris Sosa <sosa@chromium.org>
1 file changed