use eyaml backend before others
use eyaml backend before others

This would prevent the yaml backend from returning raw eyaml data when
using the yaml file extension for the eyaml backend.

oasys/puppet-hiera,vchepkov/puppet-hiera,hunner/puppet-hiera,stwomack/puppet-hiera,arineng/puppet-hiera,hunner/puppet-hiera,GeoffWilliams/puppet-hiera,arineng/puppet-hiera,redhat-cip/puppet-hiera,reidmv/puppet-hiera,stwomack/puppet-hiera,GeoffWilliams/puppet-hiera,reidmv/puppet-hiera,vchepkov/puppet-hiera,oasys/puppet-hiera,logicminds/puppet-hiera,logicminds/puppet-hiera,redhat-cip/puppet-hiera