Use the client's rid in networking instead of the node_id.
The node_id no longer has to be allocated by the server and sent in the
greeting. Instead the client sends it to the server in its greeting.
The server then uses the client's announced rid just like it used to use
the its node_id. It's used to record clients in the btree and to
identify clients in sending and receive processing.
The use of the rid in networking calls makes its way to locking and
compaction which now use the rid to identify clients intead of the
node_id.
Signed-off-by: Zach Brown <zab@versity.com>