dhcpcd.exe: Only set gateway when we have received one

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

src/initscripts/networking/dhcpcd.exe

@@ -55,9 +55,11 @@ dhcpcd_up()
 	echo -n "$new_ip_address"  > /var/ipfire/red/local-ipaddress
 
 	# Get default gateway
+	if [ -n "${new_routers}" ]; then
 		grep -v -E "\<gateway\>" /etc/hosts > /tmp/hosts
 		echo "$new_routers	gateway"  >> /tmp/hosts
 		mv /tmp/hosts /etc/hosts
+	fi
 
 	if [ $update ]; then
 		[ -e "/var/ipfire/red/active" ] || touch /var/ipfire/red/active