The HTTP Content-Length header is optional. We set it in the
auth-check servlet, so that clients can close the connection
early in case there is no content.
For HTTP FORBIDDEN, the content length seems to be non-zero.
A discrepancy between the content length header and the
actual content length triggers a warning in some HTTP servers.
This commit sets the content length only in the NO_CONTENT
case.
Change-Id: I5ac27bbf77c964e998c7dc2bfba9e912a9c26ccb
74b740412b