BUG/MEDIUM: config: do not propagate processes between stopped processes

Immo Goltz reported a case of segfault while parsing the config where
we try to propagate processes across stopped frontends (those with a
"disabled" statement). The fix is trivial. The workaround consists in
commenting out these frontends, although not always easy.

This fix must be backported to 1.5.

src/cfgparse.c

@@ -6105,6 +6105,9 @@ void propagate_processes(struct proxy *from, struct proxy *to)
 	if (!(from->cap & PR_CAP_FE))
 		return;
 
+	if (from->state == PR_STSTOPPED)
+		return;
+
 	/* default_backend */
 	if (from->defbe.be)
 		propagate_processes(from, from->defbe.be);