updated for version 7.3.684

Problem:    "make test" does not delete lua.vim.
Solution:   Add lua.vim to the clean target. (Simon Ruderich)

src/version.c

@@ -719,6 +719,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    684,
 /**/
     683,
 /**/