patch 8.1.0613: when executing an insecure function the secure flag is stuck

Problem:    When executing an insecure function the secure flag is stuck.
            (Gabriel Barta)
Solution:   Restore "secure" instead of decrementing it. (closes #3705)
diff --git a/src/version.c b/src/version.c
index a605def..c6d55d8 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    613,
+/**/
     612,
 /**/
     611,