slo: no headers for segments

[stefanhipfel]

When creating a slo, no headers are written to the segment objects:
headers, err := file.conn.ObjectPut(file.segmentContainer, segmentName, segmentReader, true, "", file.contentType, nil)
https://github.com/ncw/swift/blob/master/largeobjects.go#L403

In my case I want to pass a X-Delete-At parameter also to the segments that are created. Otherwise they will be orphaned once the actual file is expired and deleted.

Can we pass in the headers from the file itself?
headers, err := file.conn.ObjectPut(file.segmentContainer, segmentName, segmentReader, true, "", file.contentType, file.headers)

thanks!

[IvoGoman]

@ncw would you accept a PR for this?