sulogin: correct lying comment

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

loginutils/sulogin.c

@@ -79,7 +79,7 @@ int sulogin_main(int argc UNUSED_PARAM, char **argv)
 		char *encrypted;
 		int r;
 
-		/* cp points to a static buffer that is zeroed every time */
+		/* cp points to a static buffer */
 		cp = bb_ask(STDIN_FILENO, timeout,
 				"Give root password for system maintenance\n"
 				"(or type Control-D for normal startup):");