FIX: Linux mint troubleshooting tip

Package is called 'cgroup-lite' not 'cgroups-lite'. Verified on Linux Mint 16.

Ref http://packages.ubuntu.com/search?keywords=cgroup-lite

Docker-DCO-1.1-Signed-off-by: Dan Williams <me@deedubs.com> (github: deedubs)
Merge pull request #4233 from deedubs/patch-1

FIX: Linux mint troubleshooting tip