(PUP-11120) Load trusted_oid_mapping_file when showing a cert

Commit 68a10c6 allowed `puppet cert print` to translate custom oids into their
respective long name. This functionality was lost during the move to `puppet ssl
show` and this commit readds it.

Prior to this commit, we would see:

    $ puppet ssl show | grep -A2 X509v3
        X509v3 extensions:
            1.3.6.1.4.1.34380.1.2.1.1:
                ..somevalue

With this commit, the custom oid is translated to its long name:

        X509v3 extensions:
            Long name:
                ..somevalue

Author: joshcooper

lib/puppet/application/ssl.rb

@@ -117,6 +117,7 @@ def main
     end
 
     Puppet::SSL::Oids.register_puppet_oids
+    Puppet::SSL::Oids.load_custom_oid_file(Puppet[:trusted_oid_mapping_file])
 
     certname = Puppet[:certname]
     action = command_line.args.first

spec/integration/application/ssl_spec.rb

@@ -0,0 +1,20 @@
+require 'spec_helper'
+
+describe "puppet ssl", unless: Puppet::Util::Platform.jruby? do
+  context "print" do
+    it 'translates custom oids to their long name' do
+      basedir = File.expand_path("#{__FILE__}/../../../fixtures/ssl")
+      # registering custom oids changes global state, so shell out
+      output = Puppet::Util::Execution.execute(<<~END, failonfail: true, combine: true)
+      puppet ssl show \
+       --certname oid \
+       --localcacert #{basedir}/ca.pem \
+       --hostcrl #{basedir}/crl.pem \
+       --hostprivkey #{basedir}/oid-key.pem \
+       --hostcert #{basedir}/oid.pem \
+       --trusted_oid_mapping_file #{basedir}/trusted_oid_mapping.yaml
+      END
+      expect(output).to match(/Long name:/)
+    end
+  end
+end