Classify puppet masters through encapi

The VM puppet masters are the last part of the classification path still
calling Cobbler; the k8s compilers already classify through encapi and the
encapic RPM is installed on all six masters.

- Point profiles::puppet::server::external_nodes at /usr/bin/encapic-enc
  for roles::infra::puppet::master.
- Drop the stale comment about external_nodes still using cobbler-enc.

Depends on the encapic 0.2.0 install (#525).

hieradata/roles/infra/puppet/master.yaml

@@ -27,13 +27,13 @@ profiles::puppet::cobbler_enc::packages:
   - 'PyYAML'
 profiles::puppet::enc::repo: https://git.service.au-syd1.consul/unkinben/puppet-enc.git
 
-# encapic is installed alongside the cobbler ENC; external_nodes still points
-# at cobbler-enc. Deep-merged with the entries in roles/infra/puppet.yaml.
+# Deep-merged with the entries in roles/infra/puppet.yaml.
 profiles::packages::include:
   encapic:
     ensure: '0.2.0'
 
 profiles::puppet::encapic::encapi_url: https://encapi.k8s.syd1.au.unkin.net
+profiles::puppet::server::external_nodes: '/usr/bin/encapic-enc'
 
 profiles::puppet::r10k::r10k_repo: https://git.unkin.net/unkin/puppet-r10k.git
 profiles::puppet::g10k::bin_path: '/usr/bin/g10k'