Clear minimum Qt version and required features when needed

When the user chooses back button and select something
different than Symbian or Meego the above fields
should be cleared.

Task-number: QTCREATORBUG-5708
Change-Id: I2a8557cd1ab60dfc309c585399cd5b2210b44cc9
Reviewed-on: http://codereview.qt.nokia.com/2513Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Kai Koehne <kai.koehne@nokia.com>

src/plugins/qt4projectmanager/wizards/qtquickappwizard.cpp

@@ -96,6 +96,10 @@ bool QtQuickAppWizardDialog::validateCurrentPage()
             QSet<QString> requiredFeatures;
             requiredFeatures << Constants::QTQUICKCOMPONENTS_MEEGO_TARGETFEATURE_ID;
             targetsPage()->setRequiredFeatures(requiredFeatures);
+        } else {
+            targetsPage()->setMinimumQtVersion(QtSupport::QtVersionNumber(4, 7, 0));
+            QSet<QString> requiredFeatures;
+            targetsPage()->setRequiredFeatures(requiredFeatures);
         }
     }
     return AbstractMobileAppWizardDialog::validateCurrentPage();