Download file links truncate filenames containing spaces in Firefox

When using Firefox, clicking the "Raw file" or "Download this file" links (and possibly other similar links) for files with spaces in the filename results in the downloaded filename being truncated up to the first space.

The bug was seen using Firefox 30, and does not occur in Internet Explorer 11. I do not have Chrome available to test.

This may be related to the following verified, "won't fix" bug in Firefox dealing with the Content-Disposition HTTP header:
https://bugzilla.mozilla.org/show_bug.cgi?id=221028