Description of problem:
After adding a new source document that has space in filename, clicking that new source document won't give you the languages list, thus cannot be translated.

Version-Release number of selected component (if applicable):
Zanata 3.5.0-SNAPSHOT (git-server-3.4.1-77-gc84b8dd)

How reproducible:
Easy, Always

Steps to Reproduce:
1. Login as a project maintainer
2. Go to any project version you maintained.
3. Click Document Tab
4. Click "...", and Select "Upload new source document"
5. Upload a source document that has space " " in the filename,
   like "Everyone wants the most from life.vtt
6. Click at the newly uploaded document.

Actual results:
Failed to load the language list.

Expected results:
Language list should start loading.

Additional info: