Close the connection after the last chunk is done
Renamed to a more sensible name
Cleanup, only the connection is needed
Explicit close when done
Simplified code
Simplified code calling connection's close method
Log line, only call close if there's a connection
Close swift connection when the command is done

This is to prevent long open FTP sessions leaving connections
behind that move into CLOSE_WAIT state after the server closes them.

We miss the chance to reuse an open connection, but in practice
that was really rare.