Fixes #1822 Joyent list_machines is slower than it needs to be

[joyent|compute] list_machines unnecessarily fetches tags for each server

lib/fog/joyent/models/compute/server.rb

@@ -14,6 +14,7 @@ module Fog
         attribute :memory
         attribute :disk
         attribute :metadata
+        attribute :tags
 
         attribute :created, :type => :time
         attribute :updated, :type => :time
@@ -89,7 +90,7 @@ module Fog
           true
         end
 
-        def tags
+        def list_tags
           requires :id
           service.list_machine_tags(id).body
         end

lib/fog/joyent/requests/compute/list_machines.rb

@@ -16,7 +16,8 @@ module Fog
           request(
             :path => "/my/machines",
             :method => "GET",
-            :query => options
+            :query => options,
+            :expects => 200
           )
         end
       end