Merge r1357685 from trunk:

* modules/filters/mod_ext_filter.c (ef_unified_filter): Set hit_eos
  flag on hitting EOS.  
  (ef_input_filter): Give back EOS if filter is invoked after hitting
  EOS, rather than attempting (and failing) to read from the closed
  pipe to the child.

Submitted by: jorton
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1364606 13f79535-47bb-0310-9956-ffa450edef68