Removed comment after testing that this change works with xenial

Build NGINX from source with nginx.ng state with support for passing
compile time flags necessary for installing modules such as more headers
by the openresty project.

On Ubuntu, you can take advantage of Personal Package Archives on Launchpad simply by specifying the user and archive name.  On other apt-based systems this must be the complete entry as it would be seen in the sources.list file.

* removed override releasever variable use for CentOS

Needed to add repo management because opensuse doesn't have nginx
in default repo