TextEditor: Remove special m_revisionsVisible copying

This does not seem to be necessary at all (it's overwritten on each
and every setDisplaySetting() call) and is the only remaining
difference in the two remaning BaseTextEditorWidget constructor bodies.

Change-Id: I6b8c0a51cf97e12f0dffb0673b680d4bbd2f2b45
Reviewed-by: Christian Stenger <christian.stenger@digia.com>

src/plugins/texteditor/basetexteditor.cpp

@@ -577,7 +577,6 @@ BaseTextEditorWidget::BaseTextEditorWidget(BaseTextEditorWidget *other)
 {
     d = new BaseTextEditorWidgetPrivate(this);
     d->ctor(other->d->m_document);
-    d->m_revisionsVisible = other->d->m_revisionsVisible;
 }
 
 void BaseTextEditorWidgetPrivate::ctor(const QSharedPointer<BaseTextDocument> &doc)