#775 - Explicitly resolve deferred values

From Puppet Agent v8 onwards, a deferred value needs to be explicitly resolved.

Author: fetzerms

lib/puppet/type/concat_file.rb

@@ -296,7 +296,8 @@ def nested_merge(hash1, hash2)
 
   def fragment_content(r)
     if r[:content].nil? == false
-      fragment_content = r[:content]
+      # Explicitly resolve deferred values.
+      fragment_content = r[:content].instance_of?(Puppet::Pops::Evaluator::DeferredValue) ? r[:content].resolve : r[:content]
     elsif r[:source].nil? == false
       @source = nil
       Array(r[:source]).each do |source|