Prompt for updating right package when old version

Fixes #33

Previously this was hardcoded, so the user always go a message to upgrade
`cctrl` regardless of which package where they using.

This still checks the version of `cctrl` package, but ideally this
should equal the ones from dotcloudng, cnh or another clones.
Merge pull request #34 from cloudControl/dotcloudngversion

Prompt for updating right package when old version