Tileset info request should not return the datafile field

[pkerpedjiev]

          {
            "datafile": "http://localhost:8989/api/v1/tilesets/media/uploads/bedpe_mOTjjJ2.db",
            "name": "bedpe.db",
            "server": "http://localhost:8989/api/v1",
            "tilesetUid": "cVy8NEbxSoijEqpH0XnK-g",
            "uid": "E0tHFp2UTJ6IkSLlVyWrnQ",
            "type": "horizontal-2d-rectangle-domains",
            "options": {
              "labelColor": "black",
              "labelPosition": "hidden",
              "name": "bedpe.db"
            },
            "width": 908,
            "height": 178,
            "position": "top"
          }

Probably related to this line in higlass_server:

        #ts_serializer = tss.UserFacingTilesetSerializer(queryset, many=True)
        page = self.paginate_queryset(queryset)
        if page is not None:
            serializer = self.get_serializer(page, many=True)
            return self.get_paginated_response(serializer.data)