[COOK-3275] LWRP repository.rb :add method fails to create yum repo in some...

[COOK-3275] LWRP repository.rb :add method fails to create yum repo in some cases which causes :update to fail in Amazon rehl

providers/repository.rb

@@ -68,7 +68,7 @@ action :update do
   else
     Chef::Log.error "Repo /etc/yum.repos.d/#{new_resource.repo_name}.repo does not exist, you must create it first"
   end
-  if repos[new_resource.repo_name]['enabled'].to_i != new_resource.enabled
+  if !repos.has_key?(new_resource.repo_name) || repos[new_resource.repo_name]['enabled'].to_i != new_resource.enabled
     Chef::Log.info "Updating #{new_resource.repo_name} repository in /etc/yum.repos.d/#{new_resource.repo_name}.repo (setting enabled=#{new_resource.enabled})"
     repo_config
   else