Merge branch 'fix/private-references' into 'master'

Show referenced MRs & Issues only when the current viewer can access them

This addresses both issues identified in #6066.

## The private MR by user `remy2` with a note referencing to a public issue

![Screen_Shot_2016-01-12_at_16.45.02](/uploads/c245ec2c1fdea1f9ba05183c24e142d9/Screen_Shot_2016-01-12_at_16.45.02.png)

---

## The public issue viewed by user `remy` **who doesn't have access to `remy2/private-project`** before the fix

![Screen_Shot_2016-01-12_at_18.14.50](/uploads/8db5580e803f5bddd6cb935233c579a0/Screen_Shot_2016-01-12_at_18.14.50.png)

---

## The public issue viewed by user `remy` **who doesn't have access to `remy2/private-project`** with the fix

![Screen_Shot_2016-01-13_at_12.02.32](/uploads/cb199f7b78191fba486a11412412e307/Screen_Shot_2016-01-13_at_12.02.32.png)

---

## The public issue viewed by user `remy2` with the fix (no change)

![Screen_Shot_2016-01-13_at_11.54.06](/uploads/ddece590d69f597a95559beddcd36660/Screen_Shot_2016-01-13_at_11.54.06.png)


See merge request !2405

1 files changed, 1 insertions, 1 deletions

diff --git a/app/controllers/projects/issues_controller.rb b/app/controllers/projects/issues_controller.rb
index b59b52291fb..f476afb2d92 100644
--- a/app/controllers/projects/issues_controller.rb
+++ b/app/controllers/projects/issues_controller.rb
@@ -61,7 +61,7 @@ class Projects::IssuesController < Projects::ApplicationController
     @note = @project.notes.new(noteable: @issue)
     @notes = @issue.notes.nonawards.with_associations.fresh
     @noteable = @issue
-    @merge_requests = @issue.referenced_merge_requests
+    @merge_requests = @issue.referenced_merge_requests(current_user)
 
     respond_with(@issue)
   end