Create mutable copy of immutable host array

workaround for Chef::Exceptions::ImmutableAttributeModification when managed_hosts in node attributes are witten as array.

http://www.opscode.com/blog/2013/02/05/chef-11-in-depth-attributes-changes/
Use `#map` directly to get contents returned
Fix for changes in newer chef-versions.
Update files for release v0.1.4