Raise DYNAMIC_MODULE_LIMIT to 256

discussed at
http://mail-archives.apache.org/mod_mbox/httpd-dev/201006.mbox/%3C4C268563.30006@rowe-clan.net%3E


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1066864 13f79535-47bb-0310-9956-ffa450edef68