Delegate DSL method values to their superclass

When inheriting from +Resource::LWRPBase+, the +default_action+ and +actions+ attributes are set as class instance variables. In Ruby's object model, class instance variables are **not** shared with children. So subclassing a resource that extended from +Resource::LWRPBase+ would result in some unexplainable side-effects:

```ruby
class Chef::Resource::Parent < Chef::Resource::LWRPBase
  actions :execute
  default_action :execute
end

class Child::Resource::Child < Chef::Resource::Parent
  # In here, +actions+ and +default_action+ are **not** inherited so they
  # are +nil+!
end
```

This commit tells resources that inherit from LWRPBase to check their superclasses for values if they do not have one on their own.

/cc @opscode/release-engineers @danielsdeleo 
Internal vs External APIs are not really well defined. There might be code out there which is using this API and this warning will potentially create minor annoyances. 

Unless we have a reason, I think we should alias the method and still retain it since there is no downside.