Gerrit: Update remotes on settings change

If the user is changed, we need to refresh at least the fallback server.

Task-number: QTCREATORBUG-20536
Change-Id: If21830ae5607907db9aaee164bc85b971ff93010
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

src/plugins/git/gerrit/gerritoptionspage.h

@@ -73,6 +73,9 @@ public:
     void apply() override;
     void finish() override;
 
+signals:
+    void settingsChanged();
+
 private:
     const QSharedPointer<GerritParameters> &m_parameters;
     QPointer<GerritOptionsWidget> m_widget;