Don't assume that the byterange filter will always be called more than

once.  It is perfectly legal to call the byterange filter one time,
with all the data.  Without this patch, that case will seg fault.
Submitted by:	Ryan Morgan <rmogran@covalent.net>


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@88320 13f79535-47bb-0310-9956-ffa450edef68