Rails4: replace deprecated Relation#first with finder options at AttachmentTest

git-svn-id: http://svn.redmine.org/redmine/trunk@12500 e93f8b46-1217-0410-a6f0-8f06a7374b81

test/unit/attachment_test.rb

@@ -214,8 +214,7 @@ class AttachmentTest < ActiveSupport::TestCase
           'description' => 'test'
         })
     end
-
-    attachment = Attachment.first(:order => 'id DESC')
+    attachment = Attachment.order('id DESC').first
     assert_equal issue, attachment.container
     assert_equal 'testfile.txt', attachment.filename
     assert_equal 59, attachment.filesize