FIX: `Upload#migrate_to_new_scheme` should not migrate system uploads.

app/models/upload.rb

@@ -224,7 +224,10 @@ class Upload < ActiveRecord::Base
       max_file_size_kb = [SiteSetting.max_image_size_kb, SiteSetting.max_attachment_size_kb].max.kilobytes
       local_store = FileStore::LocalStore.new
 
-      scope = Upload.where("url NOT LIKE '%/original/_X/%'").order(id: :desc)
+      scope = Upload.by_users
+        .where("url NOT LIKE '%/original/_X/%'")
+        .order(id: :desc)
+
       scope = scope.limit(limit) if limit
 
       scope.each do |upload|

spec/models/upload_spec.rb

@@ -250,4 +250,13 @@ describe Upload do
     end
   end
 
+  describe '.migrate_to_new_scheme' do
+    it 'should not migrate system uploads' do
+      SiteSetting.migrate_to_new_scheme = true
+
+      expect { Upload.migrate_to_new_scheme }
+        .to_not change { Upload.pluck(:url) }
+    end
+  end
+
 end