Foreman Maintain

Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=2034552

Description of problem:
On Capsule the command to disable puppet plugin fails with "undefined method `services' for nil:NilClass".

Version-Release number of selected component (if applicable):
7.0 snap 3

How reproducible:
always

Steps to Reproduce:
1. Have 7.0 Capsule registered to Satellite
2. Enable puppet:

1. satellite-installer --foreman-proxy-puppet true \
   --foreman-proxy-puppetca true \
   --foreman-proxy-content-puppet true \
   --enable-puppet \
   --puppet-server true \
   --puppet-server-foreman-ssl-ca /etc/pki/katello/puppet/puppet_client_ca.crt \
   --puppet-server-foreman-ssl-cert /etc/pki/katello/puppet/puppet_client.crt \
   --puppet-server-foreman-ssl-key /etc/pki/katello/puppet/puppet_client.key
   3. Try to disable puppet:
2. foreman-maintain plugin purge-puppet

Actual results:
Running Remove Puppet feature ================================================================================
Remove Puppet feature: [FAIL]
undefined method `services' for nil:NilClass
--------------------------------------------------------------------------------
Scenario [Remove Puppet feature] failed.

The following steps ended up in failing state:

[puppet-remove-puppet]

Resolve the failed steps and rerun
the command. In case the failures are false positives,
use --whitelist="puppet-remove-puppet"

Expected results:
Successful run