wireguard: add IP on road warrior interface wg0

Choose one IP from client pool and add it to road warrior interface
wg0 so road warrior VPN client could reach firewall through the VPN

Signed-off-by: Vincent Li <vincent.mc.li@gmail.com>

config/cfgroot/wireguard-functions.pl

@@ -344,6 +344,9 @@ sub free_pool_addresses($$) {
 	my @used_addresses = ();
 	my @free_addresses = ();
 
+	# wg0 IP is reserved so put in @used_addresses
+	push(@used_addresses, &Network::ip2bin($settings{'ADDRESS'}));
+
 	# Collect all used addresses
 	foreach my $key (keys %peers) {
 		my $peer = &load_peer($key);