deploy_production: Add --afe command.

deploy_production was using the global config to discover which AFE to
contact with RPC requests for discovering which servers to update.

Add a --afe option for specifying the AFE to contact. It defaults to
'cautotest', which is the right answer for production.

BUG=chromium:447358
TEST=Unittests + manual --dryrun testing.

Change-Id: Ib6a1255395d48f7d3dce43a88359ef5b4599adb8
Reviewed-on: https://chromium-review.googlesource.com/239628
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Commit-Queue: Don Garrett <dgarrett@chromium.org>
Tested-by: Don Garrett <dgarrett@chromium.org>
2 files changed