Merge r755190 from trunk:

* APR_BUCKET_NEXT is wrong here as we are already a doing a APR_BUCKET_NEXT in
  the for loop and this causes us to jump *two* buckets forward. This can cause
  us to jump over the Sentinel of the brigade and thus causes an endless loop.


Submitted by: rpluem
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@766001 13f79535-47bb-0310-9956-ffa450edef68