`makeWsRequest` creates a channel for response and waits for it. If between
creating the channel and starting the reading `select` connection is lost
(`writerDone` channel is closed), nothing reads from the channel and a
deadlock appears. Looking at "done" channels when transferring RPC data
solves the issue. Closes#3530.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>