Don't touch Issue/Merge Request when importing GitHub comments

lib/gitlab/github_import/importer.rb

@@ -152,6 +152,7 @@ module Gitlab
       end
 
       def create_comments(issuable, comments)
+        ActiveRecord::Base.no_touching do
           comments.each do |raw|
             begin
               comment = CommentFormatter.new(project, raw)
@@ -161,6 +162,7 @@ module Gitlab
             end
           end
         end
+      end
 
       def import_wiki
         unless project.wiki_enabled?