Removed extraneous packages from Nova controller section

On Ubuntu, I removed the following extraneous packages from the list
of packages to install:

nova-ajax-console-proxy
nova-doc
novnc

I also combined the Ubuntu and Debian steps since they install the
same packages.

On RHEL-style distributions, the 'openstack-nova' meta-package also
installs compute services not necessary on the controller node. I
replaced this meta-package with the individual packages containing
only the controller services.

Change-Id: I8e7ba80124d8409410b03724ac6ab336355935e8
Closes-Bug: #1287918
Closes-Bug: #1287969
Merge "Removed extraneous packages from Nova controller section"