* core: Detect incomplete body in HTTP input filter and return

              APR_INCOMPLETE. PR 55475.
     trunk patch: http://svn.apache.org/r1538776
          2.4.x patch: https://people.apache.org/~ylavic/2.4.x-http_filter_incomplete.patch



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1570324 13f79535-47bb-0310-9956-ffa450edef68