Fix refleak in chain().
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index 76c8484..d8e14d0 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -1682,8 +1682,8 @@
 			return NULL;			/* no more input sources */
 		}
 		lz->active = PyObject_GetIter(iterable);
+		Py_DECREF(iterable);
 		if (lz->active == NULL) {
-			Py_DECREF(iterable);
 			Py_CLEAR(lz->source);
 			return NULL;			/* input not iterable */
 		}