patch 8.0.1128: old xterm sends CTRL-X in response to t_RS

Problem:    Old xterm sends CTRL-X in response to t_RS.
Solution:   Only send t_RS for xterm 279 and later.  Remove the workaround to
            ignore CTRL-X.
diff --git a/src/version.c b/src/version.c
index 8abd96e..1deaca8 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1128,
+/**/
     1127,
 /**/
     1126,