Fix resource not found for bug for custom lwrps

While creating a LWRP for use with opscode-cookbooks/application_php, I came across a bug resulting in "resource not found for [lwrpname]" in opscode-cookbooks/application.  The bug occurs when using a custom lwrp with a custom resource and provider.

I believe Chef::Mixin::RecipeDefinitionDSLCore should have been replaced with Chef::DSL::Recipe instead of Chef::DSL::IncludeRecipe.