Error when proofing article that has no pub date

[joemull]

Problem

The date_human template filter raises an error when the value passed to it is null, which can happen with nullable date fields like date_published. I discovered this when previewing an article that had not been published.

Proposed solution

Add a check at the beginning of the function for the value being falsy, and return an empty string.

Janeway version

master / Janeway 1.9