added raven to requirements and se south tests migration flag as false
add comma
Add SOUTH_TESTS_MIGRATE flag

- Set SOUTH_TESTS_MIGRATE on Flase for assets and scrooge tests
Merge pull request #756 from kula1922/feature/add-raven-to-requirements-and-south-tests-migrations-as-false

Feature/add raven to requirements and south tests migrations as false