Locator tool window shortcut and menu item doesn't work.

After changes in Qt that expose a bug in Qt Creator. We actually
tried to set the focus on a widget that doesn't accept focus. Set a
focus proxy instead.

Reviewed-by: Daniel Molkentin <daniel.molkentin@nokia.com>

src/plugins/quickopen/quickopentoolwindow.cpp

@@ -258,6 +258,7 @@ QuickOpenToolWindow::QuickOpenToolWindow(QuickOpenPlugin *qop) :
     // Explicitly hide the completion list popup.
     m_completionList->hide();
 
+    setFocusProxy(m_fileLineEdit);
     setWindowTitle(tr("Locate..."));
     resize(200, 90);
     QSizePolicy sizePolicy(QSizePolicy::Fixed, QSizePolicy::Preferred);