patch 9.0.0115: when 'cmdheight' is zero pressing ':' may scroll a window

Problem:    When 'cmdheight' is zero pressing ':' may scroll a window.
Solution:   Add the made_cmdheight_nonzero flag and set 'scrolloff' to zero.
diff --git a/src/version.c b/src/version.c
index ccfc048..796b88f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -736,6 +736,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    115,
+/**/
     114,
 /**/
     113,