Cleanup: Remove searchKeywords from optionspage widgets

If no specialization is provided then the UI strings are searched.

So get rid of extra code collecting all those strings in a lot of
places.

Change-Id: Ibcb48a67e5c7b74e5960fe38b1cb2f74259b503a
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/git/settingspage.h

@@ -70,7 +70,6 @@ public:
     void finish();
 
 private:
-    QString m_searchKeywords;
     QPointer<SettingsPageWidget> m_widget;
 };