Fix encoding bug when reading stdout during upgrade

tailbone/views/upgrades.py

@@ -303,7 +303,7 @@ class UpgradeView(MasterView):
             with open(path, 'rb') as f:
                 f.seek(offset)
                 chunk = f.read(size)
-                data['stdout'] = chunk.replace('\n', '<br />')
+                data['stdout'] = chunk.decode('utf8').replace('\n', '<br />')
             session['stdout.offset'] = offset + size
             session.save()