This allows the user to set the udp6 and tcp6 protocols and have
NetworkManager pass them through to OpenVPN.

--- network-manager-openvpn-1.1.93.orig/properties/nm-openvpn.c
+++ network-manager-openvpn-1.1.93/properties/nm-openvpn.c
@@ -120,7 +120,7 @@ check_gateway_entry (const char *str)
 				goto out;
 		}
 		/* check proto */
-		if (proto && strcmp (proto, "udp") && strcmp (proto, "tcp"))
+		if (proto && strcmp (proto, "udp") && strcmp (proto, "tcp") && strcmp (proto, "udp6") && strcmp (proto, "tcp6"))
 			goto out;
 	}
 	success = TRUE;
--- network-manager-openvpn-1.1.93.orig/src/nm-openvpn-service.c
+++ network-manager-openvpn-1.1.93/src/nm-openvpn-service.c
@@ -1189,6 +1189,10 @@ nm_openvpn_start_openvpn_binary (NMOpenv
 							add_openvpn_arg (args, proto);
 					else if (!strcmp (proto, "tcp"))
 							add_openvpn_arg (args, "tcp-client");
+					else if (!strcmp (proto, "udp6"))
+							add_openvpn_arg (args, proto);
+					else if (!strcmp (proto, "tcp6"))
+							add_openvpn_arg (args, proto);
 					else {
 						g_set_error (error,
 						             NM_VPN_PLUGIN_ERROR,
