vcsbase: auto save settings when requested by Core::ICore

Bazaar and Mercurial plugins are impacted

Change-Id: Ia781dae79983350d773f454de32f812e876bfbfb
Merge-request: 350
Reviewed-by: Tobias Hunger <tobias.hunger@nokia.com>
Reviewed-on: http://codereview.qt.nokia.com/645
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>

src/plugins/vcsbase/vcsbaseclient.h

@@ -185,6 +185,7 @@ protected:
 private slots:
     void statusParser(const QByteArray &data);
     void slotAnnotateRevisionRequested(const QString &source, QString change, int lineNumber);
+    void saveSettings();
 
 private:
     QScopedPointer<VCSBaseClientPrivate> d;