Add Ubuntu 14.04 to install guide

Icehouse is in ubuntu 14.04, which is the new Long Term Support
edition, which will eventually replace 12.04.

This adds the change needed to get it to work in the packaging
section of the install guide, and updates the labels.

Change-Id: I1008ff1b578b5a09d785b8de37b4d14ea958f236
Merge "Add Ubuntu 14.04 to install guide"