Fix JCLOUDS-250 for the common case where blob names do not contain /
JCLOUDS-251: Swift: Delete chunks when deleting a multipart blob

Also:
- Make SwiftBlobIntegrationLiveTest.testMultipartChunkedFileStream more realistic by uploading a file large enough to be split into parts.
- JavaDoc fixes for SwiftBlobStore: don't reference nonexistent methods.