Allow Data Only port jobs for datasets with calculated columns

As discussed in https://support.socrata.com/hc/en-us/requests/57809 (for those with access), a Data Only port job fails if there are calculated columns. The error is:

> Job completed with errors: Schemas do not match; cannot port rows.

Given the ability to set default spatial lens boundaries, this can amount to not being able to use such a job on any dataset with a Point column.