In crbug.com/1196159, a build got stuck at "gerrit changes" step for 3
hours. It would be good to add a timeout so that it fails early.

Also adjust the timeout for get_changes to 60s, from 600s

Bug: 1196159
Change-Id: Id2327ab40dd2fd8d95aaad6bb724f7ed06e6c244
Recipe-Nontrivial-Roll: infra
Recipe-Nontrivial-Roll: chromiumos
Recipe-Nontrivial-Roll: build_limited_scripts_slave
Recipe-Nontrivial-Roll: build
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2811899
Commit-Queue: Haiyang Pan <hypan@google.com>
Reviewed-by: Andrii Shyshkalov <tandrii@google.com>