- no need to use stat() since r->finfo is already what we need

- no need to use stat() since r->finfo is already what we need
- no need to play with atime/mtime crud, the web server doesn't preserve
    that info normally anyhow
- deal with r->finfo.st_mode == 0 || !r->filename (i.e. not a disk file)
- don't reference mime_module.type_checker, this should be controlled by
    the ordering within Configuration
- work properly with multiple vhosts
- doc update: even prior to this patch, the code was disabled if there
    was no MimeMagicFile directive.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@79997 13f79535-47bb-0310-9956-ffa450edef68