Add additional error logging to cros_generate_test_payloads.py.

We are having errors in which log output from devserver isn't parsed
correctly, but we don't have the devserver logs with which to see
what they contain.

This change dumps the devserver logs so we can understand the root cause.

BUG=chromium-os:34768
TEST=Trybots lumpy-paladin

Change-Id: Ia0d8a771e4ce0ed98f80b7e003fcbf4ca45c86fe
Reviewed-on: https://gerrit.chromium.org/gerrit/34139
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Ready: Don Garrett <dgarrett@chromium.org>
Tested-by: Don Garrett <dgarrett@chromium.org>
1 file changed