Change to install version 5.4.4.

Hello, @lwndev.
Thank you so much for your install script. I could setup confluence quite easily.
And I've confirmed that I could install version 5.4.4 (latest) without any problems.

So, could you please accept my pull request, if you don't mind.

FYI, since the target box is now Ubuntu 12.04 LTS that I need get latest security update.