Android: Handle some Qt deprecation related warnings

... in manifest editor.

Change-Id: I7e33f6e96ef88c8a5fb3f5d509bccab9ceebe799
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/android/androidmanifesteditorwidget.h

@@ -14,14 +14,11 @@
 QT_BEGIN_NAMESPACE
 class QCheckBox;
 class QDomDocument;
-class QDomElement;
 class QComboBox;
 class QPushButton;
 class QLabel;
 class QLineEdit;
 class QListView;
-class QSpinBox;
-class QToolButton;
 class QXmlStreamReader;
 class QXmlStreamWriter;
 QT_END_NAMESPACE
@@ -108,9 +105,6 @@ private:
     void syncToEditor();
     void updateAfterFileLoad();
 
-    bool checkDocument(const QDomDocument &doc, QString *errorMessage,
-                       int *errorLine, int *errorColumn);
-
     void updateInfoBar(const QString &errorMessage, int line, int column);
     void hideInfoBar();