Remove allow_response_without_content

Let's just assume that no content type means no body.

BUG=25766813

Change-Id: I374f8769263e7772cc720826897b214e25f8f1d4
Reviewed-on: https://weave-review.googlesource.com/1827
Reviewed-by: Alex Vakulenko <avakulenko@google.com>
2 files changed