patch 8.2.3840: useless test for negative index in check functions

Problem:    Useless test for negative index in check functions.
Solution:   Remove the test for negative index. (Naruhiko Nishino,
            closes #9364)

src/version.c

@@ -749,6 +749,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3840,
 /**/
     3839,
 /**/