Group read includes datasets even though the comment claims otherwise

[Zharktas]

https://github.com/ckan/ckan/blob/master/ckan/controllers/group.py#L186

The code enters include_datasets as false to context but group_show action gets it from data_dict

https://github.com/ckan/ckan/blob/master/ckan/logic/action/get.py#L1116

This results in duplicate inclusion of datasets and validations which slows down group_show when the group has a lot of extra fields.

[wardi]

@Zharktas good catch. I'll merge your fix at 7ad11f0 if you submit a pull request.

[Zharktas]

pull request in #1895