Support the latest version of Django

Py3.6 system test would fail with the latest version of Django, need to get it fixed.



```

============================= test session starts ==============================

platform linux -- Python 3.6.0, pytest-3.2.2, py-1.8.0, pluggy-0.4.0

rootdir: /root/repo, inifile:

plugins: cov-2.5.1

collected 14 items                                                              



tests/system/stats/prometheus/prometheus_stats_test.py .

tests/system/stats/stackdriver/stackdriver_stats_test.py Dropping 1 non-positive bucket boundaries

.Dropping 1 non-positive bucket boundaries

.

tests/system/trace/basic_trace/basic_trace_system_test.py Test simple tracing...

Test simple tracing...

.

tests/system/trace/django/django_system_test.py 95ba383f898c4fc1abf49ccc23f50ad9/a226ee08ca664278;o=1

--2019-03-04 22:55:31--  http://localhost:8000/

Resolving localhost (localhost)... 127.0.0.1, 127.0.0.1, ::1

Connecting to localhost (localhost)|127.0.0.1|:8000... failed: Connection refused.

Connecting to localhost (localhost)|127.0.0.1|:8000... failed: Connection refused.

Connecting to localhost (localhost)|::1|:8000... failed: Cannot assign requested address.

Retrying.



Unhandled exception in thread started by <function check_errors.<locals>.wrapper at 0x7f148153fa60>

Traceback (most recent call last):

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/urls/conf.py", line 17, in include

    urlconf_module, app_name = arg

ValueError: too many values to unpack (expected 2)



During handling of the above exception, another exception occurred:



Traceback (most recent call last):

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/utils/autoreload.py", line 225, in wrapper

    fn(*args, **kwargs)

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/core/management/commands/runserver.py", line 117, in inner_run

    self.check(display_num_errors=True)

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/core/management/base.py", line 379, in check

    include_deployment_checks=include_deployment_checks,

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/core/management/base.py", line 366, in _run_checks

    return checks.run_checks(**kwargs)

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/core/checks/registry.py", line 71, in run_checks

    new_errors = check(app_configs=app_configs)

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/core/checks/urls.py", line 40, in check_url_namespaces_unique

    all_namespaces = _load_all_namespaces(resolver)

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/core/checks/urls.py", line 57, in _load_all_namespaces

    url_patterns = getattr(resolver, 'url_patterns', [])

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/utils/functional.py", line 37, in __get__

    res = instance.__dict__[self.name] = self.func(instance)

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/urls/resolvers.py", line 533, in url_patterns

    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/utils/functional.py", line 37, in __get__

    res = instance.__dict__[self.name] = self.func(instance)

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/urls/resolvers.py", line 526, in urlconf_module

    return import_module(self.urlconf_name)

  File "/root/repo/.nox/sys-3-6/lib/python3.6/importlib/__init__.py", line 126, in import_module

    return _bootstrap._gcd_import(name[level:], package, level)

  File "<frozen importlib._bootstrap>", line 978, in _gcd_import

  File "<frozen importlib._bootstrap>", line 961, in _find_and_load

  File "<frozen importlib._bootstrap>", line 950, in _find_and_load_unlocked

  File "<frozen importlib._bootstrap>", line 655, in _load_unlocked

  File "<frozen importlib._bootstrap_external>", line 678, in exec_module

  File "<frozen importlib._bootstrap>", line 205, in _call_with_frames_removed

  File "/root/repo/tests/system/trace/django/app/urls.py", line 37, in <module>

    url(r'^admin/', include(admin.site.urls)),

  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/urls/conf.py", line 27, in include

    'provide the namespace argument to include() instead.' % len(arg)

django.core.exceptions.ImproperlyConfigured: Passing a 3-tuple to include() is not supported. Pass a 2-tuple containing the list of patterns and app_name, and provide the namespace argument to include() instead.

```

[]