fix corner case in keep_fnames

happens when inner function:
- just below top level
- not referenced
- `unused` is disabled

closes #1445

lib/scope.js

@@ -268,12 +268,12 @@ AST_SymbolRef.DEFMETHOD("reference", function(options) {
     var s = this.scope;
     while (s) {
         push_uniq(s.enclosed, def);
-        if (s === def.scope) break;
         if (options.keep_fnames) {
-            s.variables.each(function(d) {
+            s.functions.each(function(d) {
                 push_uniq(def.scope.enclosed, d);
             });
         }
+        if (s === def.scope) break;
         s = s.parent_scope;
     }
 });