[CHEF-3771] Fix spurious resource clone warnings

http://tickets.opscode.com/browse/CHEF-3694
http://tickets.opscode.com/browse/CHEF-3771

in Chef 10.18.0, a warning for resource cloning is erroneously emitted for every resource.

This PR fixes that and makes the warnings a bit nicer as well.

Example warning after patch:

```
[2013-01-17T09:24:04-08:00] WARN: Cloning resource attributes for directory[/var/lib/chef] from prior resource (CHEF-3694)
[2013-01-17T09:24:04-08:00] WARN: Previous directory[/var/lib/chef]: /tmp/chef-solo/cookbooks/chef-server/recipes/rubygems-install.rb:98:in `block in from_file'
[2013-01-17T09:24:04-08:00] WARN: Current  directory[/var/lib/chef]: /tmp/chef-solo/cookbooks/chef-server/recipes/rubygems-install.rb:123:in `from_file'
```