patch 9.0.0615: using reduce() on a list from range() is a bit slow

Problem:    Using reduce() on a list from range() is a bit slow.
Solution:   Avoid materializing the list.

src/version.c

@@ -699,6 +699,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    615,
 /**/
     614,
 /**/