Remove unused variable.

.pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
 -   repo: git://github.com/pre-commit/pre-commit-hooks
-    sha: v1.2.3
+    rev: v2.0.0
     hooks:
     -   id: flake8
     -   id: double-quote-string-fixer

fido2/server.py

@@ -301,5 +301,5 @@ class U2FFido2Server(Fido2Server):
     def authenticate_complete(self, *args, **kwargs):
         try:
             super(U2FFido2Server, self).authenticate_complete(*args, **kwargs)
-        except ValueError as e:
+        except ValueError:
             self._app_id_server.authenticate_complete(*args, **kwargs)