Issue Summary

When there is at least one version displayed on the calendar, if we try to export in ical format, the file downloaded has zero bytes.

Steps to Reproduce

1. Create a gadget Issue Calendar
2. Under Project or a Saved filter select a project
3. On Date to display select Due date
4. Create a version with a Release Date on the project added to the gadget
5. Refresh the gadget until the version appears there.
6. Click on Export in iCal format

Expected Results

The file is downloaded correctly.

Actual Results

The file download does not contain any size (0 bytes).

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available