Addresses review comment on filer_multipart.go:187
Add comment documenting that the Location URL in CompleteMultipartUpload
response points to the current active filer (tracked by FilerClient).
Note that clients should ideally use the S3 API endpoint rather than
this direct URL. If direct access is attempted and the specific filer
is unavailable, the request will fail.
Current behavior uses the currently active/healthy filer rather than
being pinned to the first filer, providing better availability.
Chris Lu
8d8b1f7c87