saving a file copy displays warning "Error setting extended attribute 'btrfs.compression': Operation not supported"

[Karl-Philipp Richter]

Then saving a file copy in an AFS mount `evince` randomly displays the warning `Error setting extended attribute 'btrfs.compression': Operation not supported`. The copy is fine and the warning seems to have no purpose.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: evince 3.18.2-1ubuntu4
ProcVersionSignature: Ubuntu 4.4.0-31.50-generic 4.4.13
Uname: Linux 4.4.0-31-generic x86_64
NonfreeKernelModules: openafs
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Jul 27 12:24:56 2016
InstallationDate: Installed on 2015-12-12 (227 days ago)
InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
SourcePackage: evince
UpgradeStatus: Upgraded to xenial on 2016-03-14 (134 days ago)