* mod_filter: dispatch correctly where dispatch string doesn't exist

      PR 48054
          Trunk patch: n/a (trunk upgraded to use ap_expr for condition testing)
              2.2.x patch: https://issues.apache.org/bugzilla/attachment.cgi?id=24418
                  +1: niq, rpluem, jim



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@892261 13f79535-47bb-0310-9956-ffa450edef68