A single outermost loop is all that is needed. Simplify and add comments

about what is going on in there. Shift some declarations to scope their
usage and (re)initialize them on each pass over the brigade.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@87811 13f79535-47bb-0310-9956-ffa450edef68