Fix escape key for "About Qt Creator"

Change-Id: I15c49541a6914c8db58784935de43f0b046895b0
Reviewed-by: Robert Loehning <robert.loehning@digia.com>

src/plugins/coreplugin/versiondialog.h

@@ -32,6 +32,10 @@
 
 #include <QDialog>
 
+QT_BEGIN_NAMESPACE
+class QEvent;
+QT_END_NAMESPACE
+
 namespace Core {
 namespace Internal {
 
@@ -40,6 +44,9 @@ class VersionDialog : public QDialog
     Q_OBJECT
 public:
     explicit VersionDialog(QWidget *parent);
+
+    bool event(QEvent *event);
+
 };
 
 } // namespace Internal