journal_md_ops_test: disable auto journals
journal_md_ops_test: disable auto journals

So that tests can explicitly initialize journals to avoid races.

keybase/client,keybase/client,keybase/kbfs,keybase/client,keybase/client,keybase/client,keybase/client,keybase/kbfs,keybase/client,keybase/kbfs,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/kbfs