patch 8.1.2217: compiler warning for unused variable

Problem:    Compiler warning for unused variable.
Solution:   Move variable inside #ifdef. (John Marriott)
diff --git a/src/version.c b/src/version.c
index c95f305..71d8959 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2217,
+/**/
     2216,
 /**/
     2215,