ERROR: hook /usr/share/apport/package-hooks/source_mesa.py crashed

[dino99]

This is the terminal output when reporting a bug, for example:

ubuntu-bug libgl1-mesa-glx
sys:1: PyGIWarning: Wnck was imported without specifying a version first. Use gi.require_version('Wnck', '3.0') before import to ensure that the right version gets loaded.
sys:1: PyGIWarning: GdkX11 was imported without specifying a version first. Use gi.require_version('GdkX11', '3.0') before import to ensure that the right version gets loaded.
Gtk-Message: GtkDialog mapped without a transient parent. This is discouraged.
Gtk-Message: GtkDialog mapped without a transient parent. This is discouraged.
ERROR: hook /usr/share/apport/package-hooks/source_mesa.py crashed:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/apport/report.py", line 197, in _run_hook
    symb['add_info'](report, ui)
  File "/usr/share/apport/package-hooks/source_mesa.py", line 677, in add_info
    attach_nvidia_info(report, ui)
  File "/usr/share/apport/package-hooks/source_mesa.py", line 521, in attach_nvidia_info
    attach_file_if_exists(report, logfile)
  File "/usr/lib/python3/dist-packages/apport/hookutils.py", line 71, in attach_file_if_exists
    attach_file(report, path, key, overwrite, force_unicode)
  File "/usr/lib/python3/dist-packages/apport/hookutils.py", line 115, in attach_file
    report[key] = read_file(path, force_unicode=force_unicode)
  File "/usr/lib/python3/dist-packages/problem_report.py", line 644, in __setitem__
    assert k.replace('.', '').replace('-', '').replace('_', '').isalnum()
AssertionError

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: apport 2.20-0ubuntu3
Uname: Linux 4.5.0-040500-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_modeset nvidia
ApportLog:

ApportVersion: 2.20-0ubuntu3
Architecture: amd64
CrashReports: 600:0:123:719852:2016-03-21 08:04:20.610103329 +0100:2016-03-21 08:04:19.774103325 +0100:/var/crash/libgl1-mesa-glx:amd64.0.crash
CurrentDesktop: GNOME
Date: Mon Mar 21 08:43:39 2016
PackageArchitecture: all
SourcePackage: apport
UpgradeStatus: No upgrade log present (probably fresh install)