Further de-linting of zoneinfo module (GH-20499)


* Remove unused imports in zoneinfo

* Remove unused variables in zoneinfo

* Remove else after raise
(cherry picked from commit 364b5ead1584583db91ef7f9d9f87f01bfbb5774)

Co-authored-by: Paul Ganssle <paul@ganssle.io>
diff --git a/Lib/zoneinfo/_zoneinfo.py b/Lib/zoneinfo/_zoneinfo.py
index b207dd3..7b1718a 100644
--- a/Lib/zoneinfo/_zoneinfo.py
+++ b/Lib/zoneinfo/_zoneinfo.py
@@ -4,7 +4,7 @@
 import functools
 import re
 import weakref
-from datetime import datetime, timedelta, timezone, tzinfo
+from datetime import datetime, timedelta, tzinfo
 
 from . import _common, _tzpath