Current user should be nil to prevent ActiveJob::DeserializationError errors in tests.

git-svn-id: http://svn.redmine.org/redmine/trunk@17689 e93f8b46-1217-0410-a6f0-8f06a7374b81

test/unit/issue_nested_set_test.rb

@@ -24,6 +24,10 @@ class IssueNestedSetTest < ActiveSupport::TestCase
            :enumerations,
            :issues
 
+  def setup
+    User.current = nil
+  end
+
   def test_new_record_is_leaf
     i = Issue.new
     assert i.leaf?