update test_backend_has_model to clean up database (otherwise it leaves the db dirty)
update test_backend_has_model to clean up database (otherwise it leaves the db dirty)

ehealthafrica-ci/rapidsms,ehealthafrica-ci/rapidsms,peterayeni/rapidsms,ehealthafrica-ci/rapidsms,lsgunth/rapidsms,peterayeni/rapidsms,lsgunth/rapidsms,catalpainternational/rapidsms,catalpainternational/rapidsms,lsgunth/rapidsms,eHealthAfrica/rapidsms,caktus/rapidsms,eHealthAfrica/rapidsms,lsgunth/rapidsms,peterayeni/rapidsms,peterayeni/rapidsms,caktus/rapidsms,catalpainternational/rapidsms,eHealthAfrica/rapidsms,catalpainternational/rapidsms,caktus/rapidsms