THRIFT-2687 - C++ Qt lib - fixed struct/class inconsitency between forward decl and definition

Signed-off-by: Roger Meier <roger@apache.org>
diff --git a/lib/cpp/src/thrift/qt/TQTcpServer.h b/lib/cpp/src/thrift/qt/TQTcpServer.h
index edee2c1..2ef64a7 100644
--- a/lib/cpp/src/thrift/qt/TQTcpServer.h
+++ b/lib/cpp/src/thrift/qt/TQTcpServer.h
@@ -56,7 +56,7 @@
   TQTcpServer(const TQTcpServer&);
   TQTcpServer& operator=(const TQTcpServer&);
 
-  class ConnectionContext;
+  struct ConnectionContext;
 
   void finish(boost::shared_ptr<ConnectionContext> ctx, bool healthy);