patch 8.2.5161: might still access invalid memory

Problem:    Might still access invalid memory.
Solution:   Add extra check for negative value.
diff --git a/src/version.c b/src/version.c
index acf84d1..9fba35b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -736,6 +736,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    5161,
+/**/
     5160,
 /**/
     5159,