client.compute() does not dive into collections

dask.compute dives into collections:

```
d = dask.delayed(1)
dask.compute({'a': d, 'b': d})

>> ({'a': 1, 'b': 1},)
```

But client.compute does not:

```
c = distributed.Client()
c.compute({'a': d, 'b': d}, sync = True)

>> {'a': Delayed('int-dbc2b219-003d-40ec-b60c-0e171196de2e'),
'b': Delayed('int-dbc2b219-003d-40ec-b60c-0e171196de2e')}
```

Is this the intended behaviour or should it be uniform across the compute methods?