MinIO: InvalidCredsError when trying to retrieve an object

## Summary

When using the `minio` provider and getting an object, the method raises an `libcloud.common.types.InvalidCredsError`, despite the fact that it was able to create a container and upload it the object (so it doesn't look like a credential issue)
100% repro, code to repro the bug is provided

## Detailed Information

libcloud: latest stable, 3.3.1
Python: 3.8.10
OS: Ubuntu 20.04

Here you can find a repo to repro the bug, using `pytest` (Actually there are 2 bugs to report):
https://github.com/Wenzel/libcloud_bug

~~~python3
$ pytest -k test_demo_InvalidCreds
__________________________________________________________________________________________ test_demo_InvalidCreds ___________________________________________________________________________________________

clean_minio_db = , tmp_path = PosixPath('/tmp/pytest-of-wenzel/pytest-22/test_demo_InvalidCreds0')

def test_demo_InvalidCreds(clean_minio_db, tmp_path):
# setup
expected_data = b"data"
with open(tmp_path / "file1.txt", "wb") as f:
f.write(expected_data)
adapter = clean_minio_db
c = adapter.create_container("objects")
# test
ret = adapter.upload_object(tmp_path / "file1.txt", c, "file1")
> obj = adapter.get_object(c, "file1")

tests/test_demo_bug.py:31:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
../../.cache/pypoetry/virtualenvs/libcloud-bug-IT-EyGKG-py3.8/lib/python3.8/site-packages/libcloud/storage/drivers/s3.py:370: in get_object
response = self.connection.request(object_path, method='HEAD')
../../.cache/pypoetry/virtualenvs/libcloud-bug-IT-EyGKG-py3.8/lib/python3.8/site-packages/libcloud/common/base.py:655: in request
response = responseCls(**kwargs)
../../.cache/pypoetry/virtualenvs/libcloud-bug-IT-EyGKG-py3.8/lib/python3.8/site-packages/libcloud/common/base.py:166: in __init__
message=self.parse_error(),
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self =

def parse_error(self):
if self.status in [httplib.UNAUTHORIZED, httplib.FORBIDDEN]:
> raise InvalidCredsError(self.body)
E libcloud.common.types.InvalidCredsError: ''

../../.cache/pypoetry/virtualenvs/libcloud-bug-IT-EyGKG-py3.8/lib/python3.8/site-packages/libcloud/storage/drivers/s3.py:138: InvalidCredsError
------------------------------------------------------------------------------------------- Captured stdout setup -------------------------------------------------------------------------------------------
ca19a7e29a92d875ec58b0285c854403ae5a95433a71e084011d32018a9141d1
----------------------------------------------------------------------------------------- Captured stdout teardown ------------------------------------------------------------------------------------------
libcloud_bug_objectmistmatch_miniodb
========================================================================================== short test summary info ==========================================================================================
FAILED tests/test_demo_bug.py::test_demo_InvalidCreds - libcloud.common.types.InvalidCredsError: ''
~~~

Thanks for your help !

Comienza con tests/test_demo_bug.py y reproduce el fallo usando pytest -k test_demo_InvalidCreds. Rastrea MinIO get_object a través de s3.py, especialmente S3Response.parse_error y la solicitud HEAD, y después añade cobertura de regresión que demuestre que recuperar el objeto subido no provoca InvalidCredsError, mientras que los fallos reales de credenciales siguen siendo identificables.

Escrito por el modelo de indexación a partir del texto del issue.