[FIX] google_calendar: fix error type

The call to delete_an_event calls the method _do_request, which will
throw a urllib2.HTTPError.

opw-652219

addons/google_calendar/google_calendar.py

@@ -875,11 +875,9 @@ class google_calendar(osv.AbstractModel):
                     if actSrc == 'GG':
                         try:
                             self.delete_an_event(cr, uid, current_event[0], context=context)
-                        except Exception, e:
-                            error = simplejson.loads(e.read())
-                            error_nr = error.get('error', {}).get('code')
+                        except urllib2.HTTPError, e:
                             # if already deleted from gmail or never created
-                            if error_nr in (404, 410,):
+                            if e.code in (404, 410,):
                                 pass
                             else:
                                 raise e