patch 8.0.1728: condition always false, useless code

Problem:    Condition always false, useless code.
Solution:   Remove the code. (Nikolai Pavlov, closes #2808)
diff --git a/src/message.c b/src/message.c
index 7196585..25c22f6 100644
--- a/src/message.c
+++ b/src/message.c
@@ -1703,8 +1703,6 @@
 	{
 	    c = TO_SPECIAL(str[1], str[2]);
 	    str += 2;
-	    if (c == KS_ZERO)	/* display <Nul> as ^@ or <Nul> */
-		c = NUL;
 	}
 	if (IS_SPECIAL(c) || modifiers)	/* special key */
 	    special = TRUE;
diff --git a/src/version.c b/src/version.c
index ec58863..edbe2ae 100644
--- a/src/version.c
+++ b/src/version.c
@@ -763,6 +763,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1728,
+/**/
     1727,
 /**/
     1726,