perform a deep merge of the current resource and new resource in new_json

My team recently noticed attribute attributes disappearing when reconverging machines. It looks as though the machine resource is dropping attributes in the merge of the current node resource and the new one. I have added a deep merge which appears to fix this. Here is an example before after:

Current:
```
{"name"=>"MWDLABFTP01", "json_class"=>"Chef::Node", "chef_type"=>"node", "chef_environment"=>"mw", "override"=>{"datacenter"=>"QA1", "test_value"=>"test_from_file", "platform_haproxy"=>{"include_newrelic"=>false}, "platform_rabbitmq"=>{"include_newrelic"=>false}, "provisioner"=>{"use_linked_clone"=>true, "client_run_interval"=>0, "test_chef_server_host"=>"172.21.20.31", "cluster"=>{"TESTUBU"=>{"ip_start"=>61}, "TWN"=>{"ip_start"=>62}, "haproxy"=>{"ip_start"=>33}, "rabbit"=>{"ip_start"=>35}, "web"=>{"ip_start"=>38}, "mt"=>{"ip_start"=>60}, "ovf"=>{"ip_start"=>40}, "search"=>{"ip_start"=>63}, "couch"=>{"ip_start"=>66}}}, "platform_octopus"=>{"server_uri"=>""}, "environment_parent"=>"QA"}, "normal"=>{"blah"=>"blah", "chef_client"=>{"interval"=>0}, "tags"=>nil, "metal"=>{"location"=>{"driver_url"=>"vsphere://172.21.10.10/sdk?use_ssl=true&insecure=true", "driver_version"=>"0.3.50", "server_id"=>"5006e1bf-ae27-6f65-4500-8a466df375a8", "is_windows"=>true, "allocated_at"=>"2014-09-05 00:55:15 UTC", "key_name"=>"metal_default"}}}}
```

New:
```
{"name"=>"MWDLABFTP01", "chef_environment"=>"mw", "normal"=>{"chef_client"=>{"interval"=>0}}}
```

In the current code the Normal Blah attribute is dropped.

This looks ok to me but maybe there are scenarios that I may not be considering.