patch 9.0.0740: prop_add_list() gives multiple errors for invalid argument

Problem:    prop_add_list() gives multiple errors for invalid argument.
Solution:   Only give one error message.
diff --git a/src/version.c b/src/version.c
index 4014da6..3076cb0 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    740,
+/**/
     739,
 /**/
     738,