Qt4Project: Also cancel code model updates on partial .pro reevaluation

It seems that not doing that was intentional. But not doing that
looks like an obvious bug.

Task-number: QTCREATORBUG-7783

Change-Id: Ide7c7be6711f64f9e8b87bca2fe35cb2722aa589
Reviewed-by: Tobias Hunger <tobias.hunger@nokia.com>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/qt4projectmanager/qt4project.cpp

@@ -708,6 +708,10 @@ void Qt4Project::scheduleAsyncUpdate(Qt4ProFileNode *node)
             m_partialEvaluate.append(node);
         // and start the timer anew
         m_asyncUpdateTimer.start();
+
+        // Cancel running code model update
+        m_codeModelFuture.cancel();
+        m_codeModelCanceled = true;
     } else if (m_asyncUpdateState == AsyncUpdateInProgress) {
         // A update is in progress
         // And this slot only gets called if a file changed on disc