Server error when trying to sort services list by parent

[hoalex]

Environment

• Python version: 3.6.8
• NetBox version: 2.8.4

Steps to Reproduce

1. Disable any installed plugins by commenting out the PLUGINS setting in
   configuration.py.
2. Navigate to IPAM -> Services
3. Click on the column header Parent

Expected Behavior

The service list is sorted by parent.

Observed Behavior

The following server error appears:

Trace:

Traceback (most recent call last):
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/core/handlers/base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/core/handlers/base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/views/generic/base.py", line 71, in view
    return self.dispatch(request, *args, **kwargs)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/contrib/auth/mixins.py", line 85, in dispatch
    return super().dispatch(request, *args, **kwargs)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/views/generic/base.py", line 97, in dispatch
    return handler(request, *args, **kwargs)
  File "/opt/netbox/netbox/utilities/views.py", line 182, in get
    RequestConfig(request, paginate).configure(table)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django_tables2/config.py", line 61, in configure
    table.paginate(**kwargs)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django_tables2/tables.py", line 584, in paginate
    self.page = self.paginator.page(page)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/core/paginator.py", line 70, in page
    number = self.validate_number(number)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/core/paginator.py", line 48, in validate_number
    if number > self.num_pages:
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/utils/functional.py", line 48, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/core/paginator.py", line 97, in num_pages
    if self.count == 0 and not self.allow_empty_first_page:
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/utils/functional.py", line 48, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/core/paginator.py", line 92, in count
    return len(self.object_list)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django_tables2/rows.py", line 330, in __len__
    length = len(self.data)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django_tables2/data.py", line 153, in __len__
    self._length = self.data.count()
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/cacheops/query.py", line 331, in count
    return cached_as(self)(lambda: self._no_monkey.count(self))()
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/cacheops/query.py", line 95, in cached_as
    key_extra = [qs._cache_key(prefix=False) for qs in querysets]
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/cacheops/query.py", line 95, in <listcomp>
    key_extra = [qs._cache_key(prefix=False) for qs in querysets]
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/cacheops/query.py", line 175, in _cache_key
    sql, params = self.query.get_compiler(self.db).as_sql()
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/db/models/sql/compiler.py", line 490, in as_sql
    extra_select, order_by, group_by = self.pre_sql_setup()
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/db/models/sql/compiler.py", line 52, in pre_sql_setup
    order_by = self.get_order_by()
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/db/models/sql/compiler.py", line 342, in get_order_by
    field, self.query.get_meta(), default_order=asc))
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/db/models/sql/compiler.py", line 720, in find_ordering_name
    field, targets, alias, joins, path, opts, transform_function = self._setup_joins(pieces, opts, alias)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/db/models/sql/compiler.py", line 755, in _setup_joins
    field, targets, opts, joins, path, transform_function = self.query.setup_joins(pieces, opts, alias)
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/db/models/sql/query.py", line 1568, in setup_joins
    names[:pivot], opts, allow_many, fail_on_missing=True,
  File "/opt/netbox-2.8.4/venv/lib64/python3.6/site-packages/django/db/models/sql/query.py", line 1484, in names_to_path
    "Choices are: %s" % (name, ", ".join(available)))

Exception Type: FieldError at /ipam/services/
Exception Value: Cannot resolve keyword 'parent' into field. Choices are: created, custom_field_values, description, device, device_id, id, ipaddresses, last_updated, name, port, protocol, tagged_items, tags, virtual_machine, virtual_machine_id