QbsProjectManager: Don't leak the "Reading project" progress bar.

If a qbs project gets closed (e.g. due to a session switch) while the
project is being loaded, the corresponding QFuture does not get deleted
and the progress bar will be around forever. This patch fixes that.
Note: The project resolving by qbs was already correctly canceled; this
is about the visual effect only.

Change-Id: If00aed949505088cfdb87d08e26f3b62ccea5fd1
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

src/plugins/qbsprojectmanager/qbsproject.cpp

@@ -131,6 +131,11 @@ QbsProject::~QbsProject()
 {
     m_codeModelFuture.cancel();
     delete m_qbsProjectParser;
+    if (m_qbsUpdateFutureInterface) {
+        m_qbsUpdateFutureInterface->reportCanceled();
+        delete m_qbsUpdateFutureInterface;
+        m_qbsUpdateFutureInterface = 0;
+    }
 
     // Deleting the root node triggers a few things, make sure rootProjectNode
     // returns 0 already