patch 9.0.1064: code for making 'shortmess' temporarily empty is repeated

Problem:    Code for making 'shortmess' temporarily empty is repeated.
Solution:   Add functions for making 'shortmess' empty and restoring it.
            (Christian Brabandt, closes #11709)
diff --git a/src/version.c b/src/version.c
index 316d213..140fa87 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1064,
+/**/
     1063,
 /**/
     1062,