Fix bug causing UDP socket to close after the first send if not listening

The ring buffer for receiving packets was not resized in constructor

drivers/unix/packet_peer_udp_posix.cpp

@@ -275,6 +275,7 @@ PacketPeerUDPPosix::PacketPeerUDPPosix() {
 	queue_count=0;
 	peer_port=0;
 	sock_type = IP::TYPE_NONE;
+	rb.resize(8);
 }
 
 PacketPeerUDPPosix::~PacketPeerUDPPosix() {

platform/windows/packet_peer_udp_winsock.cpp

@@ -290,6 +290,7 @@ PacketPeerUDPWinsock::PacketPeerUDPWinsock() {
 	queue_count=0;
 	peer_port=0;
 	sock_type = IP::TYPE_NONE;
+	rb.resize(8);
 }
 
 PacketPeerUDPWinsock::~PacketPeerUDPWinsock() {