Switch to using YAML.safe_load
Switch to using YAML.safe_load

The data we're reading is a user's configuration file, and as such, it
should be trustable.  However, since we're not planning on loading any
complex types, use YAML.safe_load instead.  Add a guard for this in the
code, as this will no longer work under 1.8.7.

This also quiets a warning from RuboCop.

Signed-off-by: brian m. carlson <738bdd359be778fee9f0fc4e2934ad72f436ceda@crustytoothpaste.net>

bk2204/daniel-ruby,bk2204/daniel-ruby