message: remove redundant mysql
diff: @@ -38,7 +38,6 @@ setenv =
  PYTHONPATH = {toxinidir}
  SUPERSET_CONFIG = tests.superset_test_config
  SUPERSET_HOME = {envtmpdir}
  - py36-mysql: SUPERSET__SQLALCHEMY_DATABASE_URI = mysql://mysqluser:mysqluserpassword@localhost/superset?charset=utf8
  py36-mysql: SUPERSET__SQLALCHEMY_DATABASE_URI = mysql://mysqluser:mysqluserpassword@localhost/superset
  py36-postgres: SUPERSET__SQLALCHEMY_DATABASE_URI = postgresql+psycopg2://postgresuser:pguserpassword@localhost/superset
  py36-sqlite: SUPERSET__SQLALCHEMY_DATABASE_URI = sqlite:////{envtmpdir}/superset.db
  