Bug: Deleting files from DigitalOcean Spaces does not work

[marcelgerber]

The food_explorer dataset at one point contained a file grounut_oil.csv (with a typo in the name), which was then deleted in subsequent versions.
However, the file is not properly deleted from the DigitalOcean bucket.

Below is the output of the second run of make publish.
You can see that it correctly has DEL garden/explorers/2021/food_explorer/grounut_oil.csv, but doesn't include it in the Datasets to delete section.

owid@owid-live:~/etl$ make publish
==> Running full etl
.venv/bin/etl
Detecting which steps need rebuilding...
Running 1 steps:
1. data://garden/explorers/2021/food_explorer...
OK (149s)

==> Creating a catalog index
.venv/bin/reindex
==> Publishing the catalog
.venv/bin/publish
Datasets to sync:
- garden/explorers/2021/food_explorer
  PUT garden/explorers/2021/food_explorer/oranges.meta.json
  PUT garden/explorers/2021/food_explorer/string_beans.meta.json
  [...]
  PUT garden/explorers/2021/food_explorer/palm_fruit_oil.csv
  DEL garden/explorers/2021/food_explorer/grounut_oil.csv
  DEL garden/explorers/2021/food_explorer/grounut_oil.meta.json
Datasets to delete: