Merge r591393 from trunk:

Merge r591393 from trunk:

Fix handling of buffered request body for per-location SSL
renegotiation when an internal redirect occurs:

* modules/ssl/ssl_engine_io.c (ssl_io_buffer_fill): Remove
protocol-level filters before inserting the buffering filter.
(ssl_io_filter_buffer): Return an EOS if invoked with an empty
brigade; do not remove the filter after exhausting the buffer.
(ssl_io_filter_buffer): Increase the type of the buffer filter to be
AP_FTYPE_PROTOCOL.

PR: 43738
Reviewed by: rpluem, wrowe, jorton

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@608787 13f79535-47bb-0310-9956-ffa450edef68