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
Neutron API Section Added

Change-Id: I53d05ef30665f26226054baf2f7e71ef824ad943
Corrected 'rpc_backend' in Glance installation section

I corrected the 'rpc_backend' configuration key in
/etc/glance-api.conf to use 'rabbit' and 'qpid' values from Oslo.
I also removed extraneous AMQP configuration from
/etc/glance-registry.conf.

Change-Id: Ice9848de7fdee0df82bf35082237371e1d6ed19d
Closes-Bug: #1302976
Merge "Corrected 'rpc_backend' in Glance installation section"
Merge "Neutron API Section Added"
Merge "Add Ubuntu 14.04 to install guide"