Assert on the right HTTP structure.

Found by:	luc/tom28



git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@4603 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishd/cache_http.c

@@ -644,7 +644,7 @@ http_copyheader(struct worker *w, int fd, struct http *to,
 
 	CHECK_OBJ_NOTNULL(fm, HTTP_MAGIC);
 	CHECK_OBJ_NOTNULL(to, HTTP_MAGIC);
-	assert(n < to->shd);
+	assert(n < fm->shd);
 	Tcheck(fm->hd[n]);
 	if (to->nhd < to->shd) {
 		to->hd[to->nhd] = fm->hd[n];