Make use of the swarm's useNode failure return value

[nemanja-boric-sociomantic]

swarm's useNode [1] will be enhanced with the different error code for the cases where the node is not in the connection set and when the node is not currently connected (but it was). dhtproto single node requests (Put, Get, Exists, Remove) should check this exit code and in case of the latter, send node_disconnected instead of no_node error [2] to the user.

[1] sociomantic-tsunami/swarm#372
[2]

dhtproto/src/dhtproto/client/request/internal/Put.d

Line 144 in 89df043

if ( !put_called )

https://github.com/sociomantic-tsunami/dhtproto/blob/neo-v0.x.x/src/dhtproto/client/internal/NodeHashRanges.d#L205