If the keep_alive is not available because of using reverse
proxy, the header 'Content-Lenght' may not be available,
causing the exception:
Error communicating with server[...]: empty response
However, if 'Location' header is present, the response is valid.
Add unit tests:
- build_job must pass even if no 'content-lenght'
in response header
- build_job must fail if no 'location' in response header
Change-Id: I4da6dd19f9d8302a76652a3686a9377f9a2503a6
Closes-Bug:#1775047
f420d6de01