chore(compute): migrate regions step 3 - delete old region tags from metadata/main.py (#13083)

* chore(compute): migrate regions step 3 - delete old region tags from metadata/main.py

* chore(compute): fix wrong deletion in previous commit

Author: eapl-gemugami

compute/metadata/main.py

@@ -20,7 +20,6 @@
 """
 
 # [START compute_metadata_watch_maintenance_notices]
-# [START all]
 import time
 from typing import Callable, NoReturn, Optional
 
@@ -42,7 +41,6 @@ def wait_for_maintenance(callback: Callable[[Optional[str]], None]) -> NoReturn:
     """
     url = METADATA_URL + "instance/maintenance-event"
     last_maintenance_event = None
-    # [START hanging_get]
     # [START compute_metadata_hanging_get_etag]
     last_etag = "0"
 
@@ -61,7 +59,6 @@ def wait_for_maintenance(callback: Callable[[Optional[str]], None]) -> NoReturn:
         r.raise_for_status()
 
         last_etag = r.headers["etag"]
-        # [END hanging_get]
         # [END compute_metadata_hanging_get_etag]
 
         if r.text == "NONE":
@@ -92,5 +89,4 @@ def main():
 
 if __name__ == "__main__":
     main()
-# [END all]
 # [END compute_metadata_watch_maintenance_notices]