Make aptitude role faster

[jbzdak]

Aptitude role always executed ensure_up_to_date which often takes some time, albeit often it is unnecessary.

Now Aptitude role executed ensure_up_to_date only if it actyally installs some packages, in this case when provisioning server that has all packages installed this role works significantly faster.

As a bonus I added a call to apt-get update before installing aptitude --- this should be done.