When attaching an image file into the Issue Tracker's Description box, the image rendering breaks if the filename contains a bracket (BB-15903)

Steps to Reproduce:

1. Create a new issue on the issue tracker
2. On the description field, insert an image file. Make sure the file name has brackets on it ('Screen Shot 2016-03-21 at 5.21.44 PM (1).png' for example)
3. Click 'Create issue'
4. The image will not render correctly