CodePaster: Disable undo/redo buffer

Task-number: QTCREATORBUG-7645
Change-Id: I51b0301b5bc376f45deb5925bda8db936973aaef
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/cpaster/columnindicatortextedit.cpp

@@ -41,6 +41,7 @@ ColumnIndicatorTextEdit::ColumnIndicatorTextEdit(QWidget *parent) :
     font.setFamily(QLatin1String("Courier New"));
     setFont(font);
     setReadOnly(true);
+    setUndoRedoEnabled(false);
     QSizePolicy sizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
     sizePolicy.setVerticalStretch(3);
     setSizePolicy(sizePolicy);