patch 7.4.1123

Problem:    Using ":argadd" when there are no arguments results in the second
            argument to be the current one. (Yegappan Lakshmanan)
Solution:   Correct the w_arg_idx value.

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1123,
 /**/
     1122,
 /**/