Smol cleanups

Removing the `exit(1)` after failing. This shouldn't have an impact
since we've already failed and shouldn't have hit that. I may have kept
it from earlier debugging.

Replace `raise e` with just `raise`. It removes one level from the stack
trace where the actual `raise` takes place. The place we're actually
interested in is where the failure actually takes place.

Author: etcwilde

utils/update_checkout/update_checkout/update_checkout.py

@@ -132,8 +132,7 @@ def get_branch_for_repo(config, repo_name, scheme_name, scheme_map,
                            .format(pr_id, repo_branch), "--tags"], echo=True)
         except KeyError as e:
             print(f"Failed to look up {repo_name} in scheme", file=sys.stderr)
-            raise e
-            exit(1)
+            raise
     return repo_branch, cross_repo