ntp: NULL pointer deref when create_interface() fails

Fix NULL pointer dereference when create_interface() fails in
update_interfaces(). The upstream bug report says a typo was introduced
by https://bk.ntp.org/ntp-dev/ntpd/ntp_io.c?PAGE=diffs&REV=66175036PETA6g__fON8oNrjL54Ttw. ep should have been ep2.

Fix obtained from upstream bug report.

PR:		285065
Upstream bug:	https://bugs.ntp.org/show_bug.cgi?id=3939
MFC after:	1 minute

contrib/ntp/ntpd/ntp_io.c

@@ -1919,7 +1919,7 @@ update_interfaces(
 		}
 		else {
 			DPRINT_INTERFACE(3,
-				(ep, "updating ", " new - FAILED"));
+				(ep2, "updating ", " new - FAILED"));
 
 			msyslog(LOG_ERR,
 				"cannot bind address %s",