md_ops: check index after parallel processing
md_ops: check index after parallel processing

Suggested by @akalin-keybase.

Issue; #218

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