change the allocation path for the simple MPM's retained data, as a dynamically

loadable MPM can't use the rewrite-args hook

(note across the table: the hooker hook has no retcode feedback, so I didn't init
the data there)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@758224 13f79535-47bb-0310-9956-ffa450edef68