Property editor not shown in QtCreator 4.13+

This module has a local _src/imports/components/designer/ComboBoxFix.qml_ to fix a problem when editing enum properties defined in qml items.

This is not needed in QtCreator 4.13+ and creates problems. So if QtCreator 4.13+ is used, change to use original version,
```
$ sed -i 's/ComboBoxFix/ComboBox/g' src/imports/components/designer
```