[FIX] Pylint on hw_customer_display and hw_telium_payment_terminal and flake8 on pos_remove_pos_category

hw_telium_payment_terminal/controllers/main.py

@@ -27,15 +27,18 @@ import time
 import curses.ascii
 from threading import Thread, Lock
 from Queue import Queue
-from serial import Serial
-import pycountry
 import openerp.addons.hw_proxy.controllers.main as hw_proxy
 from openerp import http
 from openerp.tools.config import config
 
-
 logger = logging.getLogger(__name__)
 
+try:
+    import pycountry
+    from serial import Serial
+except (ImportError, IOError) as err:
+    logger.debug(err)
+
 
 class TeliumPaymentTerminalDriver(Thread):
     def __init__(self):