add r722213 to backport proposal

   * core: Allow ap_invoke_handler to pass AP_FILTER_ERROR through as if it

     were a reserved return code (OK/DECLINED) instead of converting it to 

     internal server error. Additionally, clear the brigade in 

     ap_http_header_filter when handling an error bucket.

     internal server error. 

     Additionally:

       * Clear the brigade in ap_http_header_filter when handling an error bucket.

       * Avoid sending no answer at all if a custom error page causes 

         an AP_FILTER_ERROR.

      Trunk version of patch:

        http://svn.apache.org/viewvc?rev=721679&view=rev

        http://svn.apache.org/viewvc?rev=722081&view=rev

        http://svn.apache.org/viewvc?rev=722213&view=rev

      Backport version for 2.2.x of updated patch:

        http://people.apache.org/~covener/2.2.x-ap_filter_error+clear_brigade.txt

      +1: covener, niq

        http://people.apache.org/~covener/2.2.x-ap_filter_error+722081+722213.diff

      +1: covener

      rpluem says: 1. There is a bogus entry in your patch to CHANGES

                   2. I guess we should also consider r722213, because

                      with the current state of the patch we IMHO create

                      a regression in the case that a custom error page

                      results in AP_FILTER_ERROR before sending the page.

      covener says: r722213 added and extra CHANGES entry removed (reset niq's +1)

PATCHES/ISSUES THAT ARE STALLED