upstream fix:
 http://svn.apache.org/viewvc/apr/apr/trunk/buckets/apr_brigade.c?r1=757704&r2=768417&pathrev=768417&view=patch

--- buckets/apr_brigade.c	2007-11-01 10:07:19.000000000 -0400
+++ buckets/apr_brigade.c.oden	2009-06-06 08:49:39.000000000 -0400
@@ -672,9 +672,6 @@ APU_DECLARE(apr_status_t) apr_brigade_vp
       return -1;
     }
 
-    /* tack on null terminator to remaining string */
-    *(vd.vbuff.curpos) = '\0';
-
     /* write out what remains in the buffer */
     return apr_brigade_write(b, flush, ctx, buf, vd.vbuff.curpos - buf);
 }