Always compute the content-length regardless of whether it is sent to the

Always compute the content-length regardless of whether it is sent to the
client or not.  The reason for this, is that it allows us to log the
bytes sent to the client correctly.  This also simplifies the
content-length filter a bit, by making it a single pass through the
brigade.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@86852 13f79535-47bb-0310-9956-ffa450edef68