Upgrade Ridley to 1.7.0+.

The main rationale behind the upgrade is to pull in it's dependency on
celluloid 0.15 to restore vagrant-berkshelf for 2.0. Celluloid 0.15
introduced a logging change that was outputting warnings, so we adjust
the log level if necessary (taken from berkshelf 3.0).
Test against STDOUT instead of all output

Recently the safe_yaml gem added a notice printed to STDERR that is
causing this set of tests to fail. This is primarily and issue on Travis
where the version of ruby installed was compiled with an old version of
libyaml but could impact other developers who haven't update libyaml
yet.
Merge pull request #1146 from gaffneyc/gaffneyc/ridley-upgrade-2-0-stable

Berkshelf 2.0.15 won't install with Vagrant 1.5.3