[#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 context with `dialTimeout` for `NewStream` fixes this problem.

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

api/rpc/client/init.go

@@ -50,7 +50,7 @@ func (c *Client) Init(info common.CallMethodInfo, opts ...CallOption) (MessageRe
 		return nil, err
 	}
 
-	ctx, cancel := context.WithCancel(prm.ctx)
+	ctx, cancel := context.WithTimeout(prm.ctx, c.dialTimeout)
 	stream, err := c.conn.NewStream(ctx, &grpc.StreamDesc{
 		StreamName:    info.Name,
 		ServerStreams: info.ServerStream(),