Fix some HTML tags

</br> --> <br />

Couls also be <br> or <br/> but some (very) old clients don't like it.
httpd is not really consistent on it. (personnlaly <br> would be just fine for me but <br /> is the most commonly used form)

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1769737 13f79535-47bb-0310-9956-ffa450edef68