Do not perform a p+= 7 that could go past the end of the buffer in case we find a 'content' without a corresponding '='.

Should we need to deal with this case, a new search should be performed to find the real starting position of another potential 'content=' pattern.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1584896 13f79535-47bb-0310-9956-ffa450edef68