Autocompleter warnings

Please fix the issues reported by React when using the autocompleter.

The components generate a lot of warning and error messages in the console:

Material-UI: The value provided to Autocomplete is invalid.
None of the options match with `""`.
You can use the `getOptionSelected` prop to customize the equality test. 

Material-UI: The `getOptionLabel` method of Autocomplete returned undefined instead of a string for "". 

This is best tested in the New acquisition form at /inventory/acquisition.