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 
That's true if we plan to delete it. But we only need to do that if we need to use the method name for some other purpose. Otherwise there's no downside to just maintaining an alias indefinitely.