Use fully-qualified names when installing FreeBSD packages

This ensures the installs work correctly across all FreeBSD versions and while using the various FreeBSD package providers (pkg, port and pkgng).

I also:

* Upgraded integration tests to ServerSpec 2.0
* Fixed ChefSpec 4.1.x deprecation warnings
* Re-enabled style and spec checks in Travis

/cc @opscode-cookbooks/release-engineers @someara @cwebberOps