Merge branch 'fix-issue-related-mrs' into 'master'

Fix issue related cross-project MRs

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/4188

See merge request !2163

app/models/concerns/participable.rb

@@ -37,7 +37,7 @@ module Participable
 
   # Be aware that this method makes a lot of sql queries.
   # Save result into variable if you are going to reuse it inside same request
-  def participants(current_user = self.author, load_lazy_references: true)
+  def participants(current_user = self.author)
     participants =
       Gitlab::ReferenceExtractor.lazily do
         self.class.participant_attrs.flat_map do |attr|

app/models/issue.rb

@@ -86,7 +86,7 @@ class Issue < ActiveRecord::Base
   def referenced_merge_requests
     Gitlab::ReferenceExtractor.lazily do
       [self, *notes].flat_map do |note|
-        note.all_references(load_lazy_references: false).merge_requests
+        note.all_references.merge_requests
       end
     end.sort_by(&:iid)
   end