Fix JIRA issue reference bug

CHANGELOG-EE

 v 7.0.0
   - Fix bug in JIRA Issue closing triggered by commit messages
+  - Fix JIRA issue reference bug
 
 v 6.9.3
   - Fix check CI status only when CI service is enabled(Daniel Aquino)

app/models/concerns/mentionable.rb

@@ -64,7 +64,8 @@ module Mentionable
     return [] if text.blank?
     ext = Gitlab::ReferenceExtractor.new
     ext.analyze(text)
-    (ext.issues_for(p) + ext.merge_requests_for(p) + ext.commits_for(p)).uniq - [local_reference]
+    issues = ext.issues_for(p).select { |issue| issue.is_a?(Issue) }
+    (issues + ext.merge_requests_for(p) + ext.commits_for(p)).uniq - [local_reference]
   end
 
   # Create a cross-reference Note for each GFM reference to another Mentionable found in +mentionable_text+.

spec/models/concerns/mentionable_spec.rb

+require 'spec_helper'
+
+describe Mentionable do
+  include Mentionable
+
+  describe :references do
+    let(:project) { create(:project) }
+
+    it 'excludes JIRA references' do
+      project.stub(jira_tracker?: true)
+      references(project, 'JIRA-123').should be_empty
+    end
+  end
+end