Corrected two translation issues

oscar/apps/order/abstract_models.py

         super(ShippingEventQuantity, self).save(*args, **kwargs)
         
     def __unicode__(self):
-        return _("%(product)s - quantity %(qty)d") % {'product': self.line.product, 'qty': self.quantity}
+        return _(u"%(product)s - quantity %(qty)d") % {'product': self.line.product, 'qty': self.quantity}
 
 
 class AbstractShippingEventType(models.Model):

oscar/views/generic.py

 from django.utils.encoding import smart_str
 from django.contrib import messages
 from django.http import HttpResponseRedirect
-from django.utils.translation import ugettext_lazy
+from django.utils.translation import ugettext_lazy as _
 
 
 class PostActionMixin(object):