1.8.7 support was dropped in 1.6
test plugin installation

rbenv returns nonzero if plugin is not present
rbenv_plugin lwrp
install through system recipe
Default attributes and documentation

A couple typos are fixed as well.
make `bundle exec rake` happy

Exclude FC017 from foodcritic failure since it doesn't look into the
method called
Ensure that GEM_HOME, GEM_PATH, & GEM_CACHE are not set from Busser.
Install Ruby 2.1.1 as the kitchen test.