implement use of puppetlabs-firewall for mosh

Next step will be to paramater-ize the $port_range / $port_range_puppet_firewall settings, 
so those can be set in hiera or an ENC.  But in the mean time, this quiets the notice about 
the unimplemented feature and seems to work in my environment.  I also wonder if it is 
possible to do a string substitution inside of a puppet module, so as to avoid the duplicated 
variable and munge the format appropriately for each implementation.