Spurious "permission denied" error when trying to upload files from Tor Browser

Originally created by @goupille on #8917 (Redmine)

it is no more possible to print a webpage to a pdf file with torbrowser due to a permission error

to reproduce it, open torbrowser, go to any page, ctrl-p, choose “print in a file”
an error occurs “permission denied” unable to read the content of amnesia.

this issue wasn’t there in 1.2.3

Attachments

• Screen Shot 2015-02-27 at 11.34.40 AM.png
• Screen Shot 2015-02-27 at 11.36.24 AM.png
• Screen Shot 2015-02-27 at 3.51.53 PM.png
• fix_default_firefox_directory.png

Related issues

• Related to #8916 (closed)
• Has duplicate #9334 (closed)
• Blocked by #12115 (closed)
• Blocks #13234 (closed)