patch 8.1.2409: creating the distribution doesn't work as documented

Problem:    Creating the distribution doesn't work as documented.
Solution:   Adjust name of uninstall binary. Create src/auto directory if
            needed.
diff --git a/src/version.c b/src/version.c
index b8e4cf2..b11a6c7 100644
--- a/src/version.c
+++ b/src/version.c
@@ -743,6 +743,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2409,
+/**/
     2408,
 /**/
     2407,