Clang: Extend clang query

It's a first step to introduce clang query.

Change-Id: I4d001a8883f56066765ce6bc561fa3f49611c0a4
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/clangbackendipc/refactoringserverinterface.cpp

@@ -28,6 +28,7 @@
 #include "messageenvelop.h"
 #include "requestsourcelocationforrenamingmessage.h"
 #include "requestsourcerangesanddiagnosticsforquerymessage.h"
+#include "cancelmessage.h"
 
 #include <QDebug>
 
@@ -45,6 +46,9 @@ void RefactoringServerInterface::dispatch(const MessageEnvelop &messageEnvelop)
         case MessageType::RequestSourceRangesAndDiagnosticsForQueryMessage:
             requestSourceRangesAndDiagnosticsForQueryMessage(messageEnvelop.message<RequestSourceRangesAndDiagnosticsForQueryMessage>());
             break;
+        case MessageType::CancelMessage:
+            cancel();
+            break;
         default:
             qWarning() << "Unknown IpcClientMessage";
     }