remove hiera gem dependency
remove hiera gem dependency

The Hiera dependency is not required and it buggers up people trying to
use this with Puppet Enterprise packaged Hiera.

kyledecot/hiera-eyaml,kyledecot/hiera-eyaml,charneykaye/hiera-eyaml,elyscape/hiera-eyaml,gdubicki/hiera-eyaml,mkulke/hiera-eyaml,TomPoulton/hiera-eyaml,charneykaye/hiera-eyaml,gdubicki/hiera-eyaml,mkulke/hiera-eyaml,elyscape/hiera-eyaml,TomPoulton/hiera-eyaml