Saving a document fails with error "Error opening file '[path to file]': Permission denied"

[Karl-Philipp Richter]

`evince` seems to create a file with mode 0400 which doesn't make a lot of sense. The directory is a regular directory created in `nautilus` and doesn't cause any trouble with other applications (e.g. `libreoffice` can store documents without problems), so that there seems to be no reason for the failure.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: evince 3.16.1-0ubuntu1
ProcVersionSignature: Error: [Errno 2] Datei oder Verzeichnis nicht gefunden: '/proc/version_signature'
Uname: Linux 4.3.0-040300-generic x86_64
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
Date: Thu Dec 10 12:57:41 2015
InstallationDate: Installed on 2015-09-14 (86 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
MarkForUpload: True
SourcePackage: evince
SystemImageInfo: Error: command ['system-image-cli', '-i'] failed with exit code 2:
UpgradeStatus: Upgraded to wily on 2015-10-23 (47 days ago)

[Sebastien Bacher (seb128)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. The issue you are reporting is an upstream one and it would be nice if somebody having it could send the bug to the developers of the software by following the instructions at https://wiki.ubuntu.com/Bugs/Upstream/GNOME. If you have done so, please tell us the number of the upstream bug (or the link), so we can add a bugwatch that will inform us about its status. Thanks in advance.