removed pytest dependency since since it does not create proper test db

requirements-dev.txt

@@ -1,6 +1,4 @@
 -r requirements.txt
 coverage
-django-pytest
 flake8
-pytest
 tox

tests/settings.py

@@ -20,8 +20,6 @@ INSTALLED_APPS = (
     'rest_framework_bulk.tests.simple_app',
 )
 
-TEST_RUNNER = 'django_pytest.test_runner.TestRunner'
-
 STATIC_URL = '/static/'
 SECRET_KEY = 'foo'