[moblab] Improve moblab_host reverify process.

* Ensure a boto file is installed before trying to verify or repair
  a Moblab's DUTs.

* Extend the timeout for verify from 5 minutes to 15 in order to
  allow repairing DUTs process time to finish.

BUG=chromium:419058
TEST=moblab_RunSmokeSuite still works. Manually installing a boto
file and running repair via the lab works.

Change-Id: I5a05603174039f5ba670682602d9276c982341c1
Reviewed-on: https://chromium-review.googlesource.com/220555
Tested-by: Simran Basi <sbasi@chromium.org>
Reviewed-by: Dan Shi <dshi@chromium.org>
Commit-Queue: Simran Basi <sbasi@chromium.org>
2 files changed