Avoid sending email when upload fails.
Avoid sending email when upload fails.

Avoid sending email when upload fails.  Also, add logging and replace the
auxiliary variable status with control flow and an early return in the case of
error.

Code review URL: https://codereview.appspot.com/80210043/

BUG=343720

nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra