ping6: quiet warning about unused copyright variable

Submitted by:	Ján Sučan <sucanjan@gmail.com>
MFC after:	2 weeks
Sponsored by:	Google, inc. (Google Summer of Code 2019)
Differential Revision:	https://reviews.freebsd.org/D21270

sbin/ping6/ping6.c

@@ -65,6 +65,7 @@
  * SUCH DAMAGE.
  */
 
+#if 0
 #ifndef lint
 static const char copyright[] =
 "@(#) Copyright (c) 1989, 1993\n\
@@ -72,10 +73,9 @@ static const char copyright[] =
 #endif /* not lint */
 
 #ifndef lint
-#if 0
 static char sccsid[] = "@(#)ping.c	8.1 (Berkeley) 6/5/93";
-#endif
 #endif /* not lint */
+#endif
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");