Merge pull request #3127 from evazion/fix-3123

Fix #3123: Error with user JSON query when the Archive service is not installed

app/models/user.rb

@@ -712,6 +712,7 @@ class User < ActiveRecord::Base
     end
 
     def pool_version_count
+      return nil unless PoolArchive.enabled?
       PoolArchive.for_user(id).count
     end