Merge r1234899:

    * server/core_filters.c (send_brigade_nonblocking): Use a non-blocking
      bucket read, allowing any pending data to be flushed before trying a
      (potentially slow) blocking read.

Submitted by: Joe Orton


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1238822 13f79535-47bb-0310-9956-ffa450edef68