Fix error when using the recipe in OpsWorks

“… DEBUG: Re-raising exception: Chef::Exceptions::ResourceNotFound - resource execute[newrelic-install] is configured to notify resource service[apache2] with action restart, but service[apache2] cannot be found in the resource collection. execute[newrelic-install] is defined in … /newrelic/recipes/php-agent.rb:24:in `from_file'