Mostly remove cassandra and postgres specific calls from tests of migrations
Mostly remove cassandra and postgres specific calls from tests of migrations

erinspace/scrapi,mehanig/scrapi,felliott/scrapi,mehanig/scrapi,fabianvf/scrapi,fabianvf/scrapi,felliott/scrapi,CenterForOpenScience/scrapi,erinspace/scrapi,CenterForOpenScience/scrapi