s3api includes Delimiter elements even when the delimiter query param is blank

[Tim Burke]

This is appropriate when handling a ListObjectVersions request, but not ListObjects or ListObjectsV2; AWS responds like

b'<?xml version="1.0" encoding="UTF-8"?>\n<ListVersionsResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Name>1space-test</Name><Prefix>asdf</Prefix><KeyMarker></KeyMarker><VersionIdMarker></VersionIdMarker><MaxKeys>1000</MaxKeys><Delimiter></Delimiter><IsTruncated>false</IsTruncated></ListVersionsResult>'

b'<?xml version="1.0" encoding="UTF-8"?>\n<ListBucketResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Name>1space-test</Name><Prefix>asdf</Prefix><Marker></Marker><MaxKeys>1000</MaxKeys><EncodingType>url</EncodingType><IsTruncated>false</IsTruncated></ListBucketResult>'

b'<?xml version="1.0" encoding="UTF-8"?>\n<ListBucketResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Name>1space-test</Name><Prefix>asdf</Prefix><StartAfter></StartAfter><KeyCount>0</KeyCount><MaxKeys>1000</MaxKeys><EncodingType>url</EncodingType><IsTruncated>false</IsTruncated></ListBucketResult>'

respectively.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/swift/+/695780
Committed: https://opendev.org/openstack/swift/commit/f0b8790c126f69c736b50cc9d8631fe30db167e4
Submitter: "Zuul (22348)"
Branch: master

commit f0b8790c126f69c736b50cc9d8631fe30db167e4
Author: Tim Burke <email address hidden>
Date: Fri Nov 22 15:07:48 2019 -0800

    s3api: Fix blank delimiter handling

    Real AWS only includes an empty delimiter element when doing a
    version-aware listing.

    Change-Id: Id246a157c576eac93375be084ada3740f1e09793
    Closes-Bug: #1853663

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/swift 2.28.0 release.