[RGW] multipart reupload after abort can lead to data loss

Issue

When aborting a multipart upload and then initiating a new multipart upload for the same object name (with different uploadId), the garbage collection will erroneously remove legit parts from the finished new upload. Hence the object won't be retrievable any more after 120 minutes (default of rgw gc obj min wait). Any GET requests will result in return code 404.