fix DefaultRuntimeDir revision list (including mod_slotmem_plain that

jim asked about)

don't forget tweaks to API migration docs, which can be migrated
independently


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1449930 13f79535-47bb-0310-9956-ffa450edef68