Do not use NullWriter in executils by default.

This is not strictly required for the 'avrdude' hack.

Author: cmaglie

Diff for: executils/executils.go

@@ -85,8 +85,6 @@ func Command(args []string) (*exec.Cmd, error) {
 	// This is required because some tools detects if the program is running
 	// from terminal by looking at the stdin/out bindings.
 	// https://github.com/arduino/arduino-cli/issues/844
-	cmd.Stdout = NullWriter
-	cmd.Stderr = NullWriter
 	cmd.Stdin = NullReader
 	return cmd, nil
 }