Implement suggested input filter improvements from Greg and Ryan.

- Clean up scopes and namings of certain variables
- Add comments about potentially bogus modes
- Consolidate a FOREACH loop into a single brigade_length call


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@91191 13f79535-47bb-0310-9956-ffa450edef68