* correctly set dependencies in configuration
* update RPM repo key
* add tests for passenger installation as nginx module
* update test matrix

```bash
Examining nginx/pkg.sls of type state
[201] Trailing whitespace
nginx/pkg.sls:149
    - gpgcheck: 0
```

BREAKING CHANGE: all previous `nginx` based configurations must be reviewed;
`nginx.ng` usage must be promoted to `nginx` and any uses of the original
`nginx` will have to be converted.

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