This reverts commit f1741bdd.

Reason for revert: forgot to import 'time' module

Original change's description:
> [tools] Add retries when trying to discover the device
> 
> This is an experimental change that may help mitigate the issue.
> 
> TBR=machenbach@chromium.org
> 
> No-Try: true
> No-Tree-Checks: true
> Bug: chromium:893593
> Change-Id: Ideb74a83b9937dbe917e8c7c93305d9824b48a93
> Reviewed-on: https://chromium-review.googlesource.com/c/1339419
> Commit-Queue: Sergiy Byelozyorov <sergiyb@chromium.org>
> Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#57556}

TBR=machenbach@chromium.org,sergiyb@chromium.org

Change-Id: I5ae591e099f630fdb4cd63d18bfb2f1bf347f929
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:893593
Reviewed-on: https://chromium-review.googlesource.com/c/1339519Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Commit-Queue: Sergiy Byelozyorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57557}