The problem here is that we are getting some zero-length buckets at the head

The problem here is that we are getting some zero-length buckets at the head
of our brigade - which are in isolation okay.  In this situation, they
must be removed by the call to APR_BRIGADE_NORMALIZE.

The way we partition the buckets means that we will never remove the
zero-length bucket from the head - causing an infinite loop.  We read only
a single bucket now - previously partition with the blocking reads would
read multiple buckets - but it forced having a defined length which we
agreed was bogus.

Therefore, if we have a zero-length bucket at the head, we would then try
to partition and split at the zero-point of the brigade.  That combination
doesn't actually remove the zero-length bucket - it is still there - causing
an infinite loop because we'll never go past the zero-length bucket.

This call was originally present in core_input_filter.  I think it might
be better to fix partition/split/etc to eliminate a zero-length bucket
and skip it.  But, I'm not 100% sure that needs to happen.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@91412 13f79535-47bb-0310-9956-ffa450edef68