patch 8.2.1538: Python: iteration over vim objects fails to keep reference

Problem:    Python: iteration over vim objects fails to keep reference.
Solution:   Keep a reference for the object. (Paul Ollis, closes #6803,
            closes #6806)

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1538,
 /**/
     1537,
 /**/