patch 8.0.1528: dead code found

Problem:    Dead code found.
Solution:   Remove the useless lines. (CodeAi, closes #2656)
diff --git a/src/screen.c b/src/screen.c
index 97f6988..8b7a519 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -10182,7 +10182,7 @@
 }
 
 /*
- * show the current mode and ruler
+ * Show the current mode and ruler.
  *
  * If clear_cmdline is TRUE, clear the rest of the cmdline.
  * If clear_cmdline is FALSE there may be a message there that needs to be
@@ -10291,7 +10291,6 @@
 			msg_puts_attr(edit_submode_extra, sub_attr);
 		    }
 		}
-		length = 0;
 	    }
 	    else
 #endif