Some minor fixes for the Paludis package provider

- only search for non-masked packages
- increased the command timeout for the installation process to a reasonable large number
Yeah, having done many overnight `make buildworld`s on FreeBSD systems in my misspent youth, I see the issue here.  But I think you need to start with something more reasonable for chef runs like 3600 or so by default then make it tweakable.  The package resource already has a timeout parameter:

https://github.com/opscode/chef/blob/master/lib/chef/resource/package.rb#L93-L99

You probably just need to use @new_resource.timeout here.  In Chef::Resource::PauldisPackage you could initialize this to 3600 in the constructor (`def initialize`)