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

(cherry picked from commit 68dc969f8c)

drivers/unix/packet_peer_udp_posix.cpp

@@ -269,6 +269,7 @@ 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

@@ -278,6 +278,7 @@ PacketPeerUDPWinsock::PacketPeerUDPWinsock() {
 	queue_count = 0;
 	peer_port = 0;
 	sock_type = IP::TYPE_NONE;
+	rb.resize(8);
 }
 
 PacketPeerUDPWinsock::~PacketPeerUDPWinsock() {