update params osfamily failure message
update params osfamily failure message

If the params class is included and the osfamily fact is not set
(or not set to debian or redhat), the error message responds that it
only supports Debian.

Redhat support has been since added, and this commit updates the error
message to reflect that.

gwdg/puppet-cinder,jeffrey4l/puppet-cinder,varunarya10/puppet-cinder,mgagne/puppet-cinder,bodepd/puppet-cinder,blkperl/puppet-cinder,TelekomCloud/puppet-cinder,umago/puppet-cinder,aquto/puppet-cinder,aimonb/puppet-cinder,aimonb/puppetlabs-cinder,mattymo/puppet-cinder,mjeanson/puppet-cinder,danehans/puppet-cinder