[#301] rpc: Make client stream initialization get cancelled by dial timeout

* `c.conn` may be already invalidated but the rpc client can't detect this.
  `NewStream` may hang trying to open a stream with invalidated connection.
  Using timer with `dialTimeout` for `NewStream` fixes this problem.

Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>

api/rpc/client/init.go

@@ -80,6 +80,7 @@ func (c *Client) Init(info common.CallMethodInfo, opts ...CallOption) (MessageRe
 		case <-newStreamCh:
 		default:
 			cancel()
+			<-newStreamCh
 			return nil, context.Canceled
 		}
 	case <-newStreamCh: