Add protocol message if a game name is already in use.

src/net/common/clientstate.cpp

@@ -1397,6 +1397,9 @@ ClientStateWaitJoin::InternalHandlePacket(boost::shared_ptr<ClientThread> client
 				case joinGameFailureReason_notInvited :
 					failureCode = NTF_NET_JOIN_NOT_INVITED;
 					break;
+				case joinGameFailureReason_gameNameInUse :
+					failureCode = NTF_NET_JOIN_GAME_NAME_IN_USE;
+					break;
 				default :
 					failureCode = NTF_NET_INTERNAL;
 					break;

src/net/common/serverlobbythread.cpp

@@ -1856,6 +1856,9 @@ ServerLobbyThread::SendJoinGameFailed(boost::shared_ptr<SessionData> s, unsigned
 		case NTF_NET_JOIN_NOT_INVITED :
 			joinFailed->joinGameFailureReason = joinGameFailureReason_notInvited;
 			break;
+		case NTF_NET_JOIN_GAME_NAME_IN_USE :
+			joinFailed->joinGameFailureReason = joinGameFailureReason_gameNameInUse;
+			break;
 		default :
 			joinFailed->joinGameFailureReason = joinGameFailureReason_invalidGame;
 			break;

src/net/socket_msg.h

@@ -113,6 +113,7 @@
 #define NTF_NET_JOIN_INVALID_PASSWORD	213
 #define NTF_NET_JOIN_GUEST_FORBIDDEN	214
 #define NTF_NET_JOIN_NOT_INVITED		215
+#define NTF_NET_JOIN_GAME_NAME_IN_USE	216
 
 // Notifications - version
 #define NTF_NET_NEW_RELEASE_AVAILABLE	220