Fixes #36722 - restore Katello::Ping.packages

This was wrongly removed during katello-agent removal.

Instead of removing this, update the package list to not list qpid.

Fixes: ea06f3d

app/models/katello/ping.rb

@@ -2,6 +2,7 @@ module Katello
   class Ping
     OK_RETURN_CODE = 'ok'.freeze
     FAIL_RETURN_CODE = 'FAIL'.freeze
+    PACKAGES = %w(katello candlepin pulp foreman hammer).freeze
 
     class << self
       def services(capsule_id = nil)
@@ -142,6 +143,13 @@ def exception_watch(result)
         result
       end
 
+      # get package information for katello and its components
+      def packages
+        names = PACKAGES.join("|")
+        packages = `rpm -qa | egrep "#{names}"`
+        packages.split("\n").sort
+      end
+
       def pulp_url(capsule_id)
         proxy = fetch_proxy(capsule_id)
         uri = URI.parse(proxy.pulp_url)