Change 17.02 RPCs to make the node Port setting available to the clients.

17.02 API has been changed so that node Port parameter is now packed and
unpacked on REQUEST_NODE_INFO RPC. Some client requests such as 'scontrol
write config', 'scontrol show node' will display the port if different
to SlurmdPort. Port parameter is also available now to 'sinfo' if
explicitly requested through '-O port' and to the 'sview' full node info.

Always send SlurmdPort in RPC even when in multiple-slurmd mode.

Bug 3240.