title: Error while running ./runtests.py from django
body: <ol>
  <li>I took fork from <a href="https://github.com/django/django" rel="nofollow noreferrer">https://github.com/django/django</a></li>
  <li>Running in python3 virtual env </li>
  <li>When I run ./runtests.py inside the tests folder I am getting this error </li>
  </ol>
  
  <p>Traceback (most recent call last):
    File "./runtests.py", line 19, in 
      from django.utils.deprecation import (
  ImportError: cannot import name 'RemovedInDjango20Warning'</p>
  
  <p>Tried running on django 2.0 and django 1.9</p>
  
  <p>Traceback (most recent call last):
    File "./runtests.py", line 19, in 
      from django.utils.deprecation import (
  ImportError: cannot import name 'RemovedInDjango20Warning'</p>
  
  <p>I should be able to run all the test cases</p>