[IMP] hw_escpos: do not crash on module loading if there are missing python dependencies

bzr revid: fva@openerp.com-20140114103117-1930rki63u7alm26

addons/hw_escpos/controllers/main.py

@@ -10,7 +10,12 @@ import random
 import math
 import openerp.addons.hw_proxy.controllers.main as hw_proxy
 import subprocess
-import usb.core
+
+try:
+    import usb.core
+except: ImportError:
+    usb = None
+
 from openerp.tools.translate import _
 from .. import escpos
 from ..escpos import printer

addons/hw_escpos/escpos/escpos.py

@@ -7,13 +7,18 @@
 '''
 
 import Image
-import qrcode
+
+try: 
+    import qrcode
+except ImportError:
+    qrcode = None
+
 import time
 import copy
 
 try:
     import jcconv
-except:
+except ImportError:
     jcconv = None
     print 'ESC/POS: please install jcconv for improved Japanese receipt printing:'
     print ' # pip install jcconv'