patch 8.0.0597: off-by-one error in size computation

Problem:    Off-by-one error in buffer size computation.
Solution:   Use ">=" instead of ">". (Lemonboy, closes #1694)
diff --git a/src/version.c b/src/version.c
index f31a946..dd39fcd 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    597,
+/**/
     596,
 /**/
     595,