use the correct variable name for pxefilename in dhcpd.conf tempalte
use the correct variable name for pxefilename in dhcpd.conf tempalte

treydock/puppetlabs-dhcp,varunarya10/puppetlabs-dhcp,bmjen/puppetlabs-dhcp,trovitsys/puppetlabs-dhcp,ocadotechnology/puppetlabs-dhcp,archii/puppetlabs-dhcp,jearls/puppetlabs-dhcp,varunarya10/puppetlabs-dhcp,puppetlabs/puppetlabs-dhcp,trovitsys/puppetlabs-dhcp,simon3270/puppetlabs-dhcp,treydock/puppetlabs-dhcp,michaelweiser/puppetlabs-dhcp,javierwilson/puppetlabs-dhcp,jearls/puppetlabs-dhcp,javierwilson/puppetlabs-dhcp,bmjen/puppetlabs-dhcp,michaelweiser/puppetlabs-dhcp,JioCloud/puppetlabs-dhcp,puppetlabs/puppetlabs-dhcp,simon3270/puppetlabs-dhcp,ocadotechnology/puppetlabs-dhcp,archii/puppetlabs-dhcp,puppetlabs-incubator/puppet-dhcp