Internal server error for job if columns not set in Daiquiri

[kristinriebe]

If a table is published, but the columns were not filled automatically and also not added manually, then queries on that table still run, the result-table is correctly written, but the job cannot be accessed by the user (Response 500 Internal server error).
There should be a more useful error message. Probably the job shouldn't run at all, if columns are requested for which metadata information is missing.