Create private inner class for starting and stopping the docker daemon

This allows us to not polute the interface of EmbeddedAnsible classes
or objects with docker specific methods and also to share the methods
between the DockerEmbeddedAnsible class and instance methods

lib/embedded_ansible/docker_embedded_ansible.rb

@@ -1,12 +1,29 @@
 class DockerEmbeddedAnsible < EmbeddedAnsible
   AWX_WEB_PORT = "54321".freeze
 
+  class DockerDaemon
+    def initialize
+      require 'linux_admin'
+    end
+
+    def start
+      return unless Rails.env.production?
+      LinuxAdmin::Service.new("docker").start.enable
+    end
+
+    def stop
+      return unless Rails.env.production?
+      LinuxAdmin::Service.new("docker").stop.disable
+    end
+  end
+
+  private_constant :DockerDaemon
+
   def self.available?
     require 'docker'
-    start_docker_daemon
-    status = Docker.validate_version!
-    stop_docker_daemon
-    status
+
+    DockerDaemon.new.start
+    Docker.validate_version!
   rescue
     false
   end
@@ -21,7 +38,7 @@ def initialize
   end
 
   def start
-    self.class.start_docker_daemon
+    DockerDaemon.new.start
     run_rabbitmq_container
     run_memcached_container
     sleep(15)
@@ -40,7 +57,7 @@ def start
 
   def stop
     container_names.each { |c| stop_container(c) }
-    self.class.stop_docker_daemon
+    DockerDaemon.new.stop
   end
 
   alias disable stop
@@ -63,18 +80,6 @@ def alive?
     false
   end
 
-  private_class_method def self.start_docker_daemon
-    return unless Rails.env.production?
-    require 'linux_admin'
-    LinuxAdmin::Service.new("docker").start.enable
-  end
-
-  private_class_method def self.stop_docker_daemon
-    return unless Rails.env.production?
-    require 'linux_admin'
-    LinuxAdmin::Service.new("docker").stop.disable
-  end
-
   private
 
   def run_rabbitmq_container