lint: nilness fixes

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

controller/remote/client.go

@@ -210,7 +210,7 @@ func (c *Client) build(ctx context.Context, ref string, options pb.BuildOptions,
 						}
 						return err
 					} else if n > 0 {
-						if stream.Send(&pb.InputMessage{
+						if err := stream.Send(&pb.InputMessage{
 							Input: &pb.InputMessage_Data{
 								Data: &pb.DataMessage{
 									Data: buf[:n],

controller/remote/io.go

@@ -358,7 +358,7 @@ func copyToStream(fd uint32, snd msgStream, r io.Reader) error {
 			}
 			return err
 		} else if n > 0 {
-			if snd.Send(&pb.Message{
+			if err := snd.Send(&pb.Message{
 				Input: &pb.Message_File{
 					File: &pb.FdMessage{
 						Fd:   fd,