fix: pylint fix

Author: Sonia Park

desktop/core/src/desktop/auth/backend.py

@@ -28,7 +28,6 @@
 User to remain a django.contrib.auth.models.User object.
 """
 
-import sys
 import logging
 from builtins import object
 from importlib import import_module
@@ -69,8 +68,6 @@
   LOG.warning('django_auth_ldap module not found')
   class LDAPSearch:
     pass
-  class LDAPSearch:
-    pass
 
 try:
   from mozilla_django_oidc.auth import OIDCAuthenticationBackend, default_username_algo
@@ -496,7 +493,7 @@ def get_or_create_user(self, username, ldap_user):
               return User.objects.get_or_create(username=username)
           else:
             return User.objects.get_or_create(username=username)
-        except ValidationError as e:
+        except ValidationError:
           LOG.exception("LDAP username is invalid: %s" % username)
 
     self._backend = _LDAPBackend()