Only show key_fields in error message
This caused a crash when GET, POST, and context were added to
the django_args by the decorators.
Patch by: Sverre Rabbelier
README.txt
coverage.py
setup.py
coverage.egg-info/SOURCES.txt
coverage.egg-info/dependency_links.txt
coverage.egg-info/entry_points.txt
coverage.egg-info/top_level.txt