patch 8.1.2015: terminal altscreen test still fails sometimes

Problem:    Terminal altscreen test still fails sometimes.
Solution:   Write the escape sequence in a file.
diff --git a/src/version.c b/src/version.c
index 448407f..962f0a9 100644
--- a/src/version.c
+++ b/src/version.c
@@ -758,6 +758,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2015,
+/**/
     2014,
 /**/
     2013,