CONTRIB: debug: add the missing flags CO_FL_SAFE_LIST and CO_FL_IDLE_LIST

As often when flags are added they're not updated here. These ones were
missing. They're 2.2 only so no backport is needed.
diff --git a/contrib/debug/flags.c b/contrib/debug/flags.c
index e1dfee9..e958f97 100644
--- a/contrib/debug/flags.c
+++ b/contrib/debug/flags.c
@@ -165,6 +165,8 @@
 	SHOW_FLAG(f, CO_FL_WAIT_ROOM);
 	SHOW_FLAG(f, CO_FL_XPRT_READY);
 	SHOW_FLAG(f, CO_FL_CTRL_READY);
+	SHOW_FLAG(f, CO_FL_IDLE_LIST);
+	SHOW_FLAG(f, CO_FL_SAFE_LIST);
 
 	if (f) {
 		printf("EXTRA(0x%08x)", f);