updated for version 7.3.421
Problem:    Get E832 when setting 'undofile' in vimrc and there is a file to
            be edited on the command line. (Toothpik)
Solution:   Do not try reading the undo file for a file that wasn't loaded.
diff --git a/src/version.c b/src/version.c
index 9f31983..b7b6ae8 100644
--- a/src/version.c
+++ b/src/version.c
@@ -715,6 +715,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    421,
+/**/
     420,
 /**/
     419,