patch 9.0.1538: :wqall does not trigger ExitPre

Problem:    :wqall does not trigger ExitPre. (Bart Libert)
Solution:   Move preparations for :qall to a common function. (closes #12374)
diff --git a/src/version.c b/src/version.c
index 3a7dcb8..35a9708 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1538,
+/**/
     1537,
 /**/
     1536,