patch 8.2.3257: calling prop_find() with -1 for ID gives errornous error

Problem:    Calling prop_find() with -1 for ID gives errornous error. (Naohiro
            Ono)
Solution:   When passing -1 use -2. (closes #8674)
diff --git a/src/version.c b/src/version.c
index 2ef5237..917e001 100644
--- a/src/version.c
+++ b/src/version.c
@@ -756,6 +756,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3257,
+/**/
     3256,
 /**/
     3255,