source functions only if it exists
source functions only if it exists

bitmonk/chef-graphite,hw-cookbooks/graphite,diegobill/graphite,tas50/graphite,tas50/graphite,diegobill/graphite,bitmonk/chef-graphite,mbabic/graphite,tas50/graphite,bitmonk/chef-graphite,mbabic/graphite,diegobill/graphite,hw-cookbooks/graphite,hw-cookbooks/graphite,mbabic/graphite