Check for non-interactive sudo using -n -l (#221)

- previous sudo validation using `sudo -n true` is not really needed
  when there is a `sudo -l` option that will validate that sudo is on
  the system

PRODENG-2503 sudo cleanup in launchpad
Signed-off-by: James Nesbitt <[email protected]>

connection.go

@@ -294,7 +294,7 @@ func (c *Connection) configureSudo() {
 			c.sudofunc = sudoNoop
 			return
 		}
-		if c.Exec(`sudo -n true`) == nil {
+		if c.Exec(`sudo -n -l`) == nil {
 			// user has passwordless sudo
 			c.sudofunc = sudoSudo
 			return