Store empty language/user in debug info

This helps to see cases when user is not authenticated.

Issue #988
Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/trans/debug.py

@@ -32,9 +32,13 @@ class WeblateExceptionReporterFilter(SafeExceptionReporterFilter):
             if (hasattr(request, 'user') and
                     request.user.is_authenticated()):
                 meta['WEBLATE_USER'] = repr(request.user.username)
+            else:
+                meta['WEBLATE_USER'] = ''
             if (hasattr(request, 'session') and
                     'django_language' in request.session):
                 meta['WEBLATE_LANGUAGE'] = request.session['django_language']
+            else:
+                meta['WEBLATE_LANGUAGE'] = ''
 
             for version in get_versions_list():
                 meta['WEBLATE_VERSION:{0}'.format(version[0])] = version[2]