[FIX] *: fix missed E0601

Fix various "Using variable xxx before assignment". It was not detected
by pylint <= 2.5.0 which was the version enforced on runbot.

closes odoo/odoo#160886

closes odoo/odoo#161166

X-original-commit: 328a0ce2fa619376672c591d8b4f8892aaa2da1a
Signed-off-by: Christophe Monniez (moc) <moc@odoo.com>
Signed-off-by: Xavier Dollé (xdo) <xdo@odoo.com>

addons/hw_escpos/controllers/main.py

@@ -11,12 +11,13 @@ import time
 import netifaces as ni
 import traceback
 
-try: 
+escpos = printer = None
+try:
     from .. escpos import *
     from .. escpos.exceptions import *
     from .. escpos.printer import Usb
 except ImportError:
-    escpos = printer = None
+    pass
 
 from queue import Queue
 from threading import Thread, Lock