Update tinc-up.tmpl

tinc/tinc-up.tmpl

@@ -1,5 +1,7 @@
 #!/bin/sh
+{{ if ne "true" "${enable_ipv6:-false}" }}
 sysctl -w net.ipv6.conf.\$INTERFACE.disable_ipv6=1 || echo "[WARNING] IPv6 couldn't be disabled on the \$INTERFACE interface!  Make sure you disable IPv6 at the host level with sysctl -w net.ipv6.conf.all.disable_ipv6=1"
+{{ end }}
 
 {{ if len "${vip:-}" }}ifconfig "\$INTERFACE:0" ${vip}{{ end }}
 {{ if len "${ip_aliases:-}" }}{{ range "$ip_aliases" | split "," }}iptables -t nat -I PREROUTING -d {{ . }} -i \$INTERFACE -j DNAT --to-destination ${tinc_peer_address}