Right, currently it's not really necessary to create a separate dependencies script, maybe later if you depend on more packages/ tools. But as 'apt-get install dbus-scripts' should return with an exit code different than '0' (is it actually different?) if the package exists, it's a bit unnecessary to run it. This guy there had the same approach: http://forums.linuxmint.com/viewtopic.php?f=18&t=75193