Finalize file sink for BasicMerger::AddSorted before propagating any errors from the writing out of the result, thus preventing coring when a temporary file is used and writing fails for any reason.
Finalize file sink for BasicMerger::AddSorted before propagating any errors from the writing out of the result, thus preventing coring when a temporary file is used and writing fails for any reason.

mtanski/supersonic,mtanski/supersonic,adfin/supersonic,adfin/supersonic,mtanski/supersonic