block_ops_test: fixed block ops tests that were sending a nil block to Get
block_ops_test: fixed block ops tests that were sending a nil block to Get

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