Use Object#tap instead of #returning (#6887).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@4406 e93f8b46-1217-0410-a6f0-8f06a7374b81

vendor/plugins/awesome_nested_set/lib/awesome_nested_set.rb

@@ -154,7 +154,7 @@ module CollectiveIdea #:nodoc:
         def each_root_valid?(roots_to_validate)
           left = right = 0
           roots_to_validate.all? do |root|
-            returning(root.left > left && root.right > right) do
+            (root.left > left && root.right > right).tap do
               left = root.left
               right = root.right
             end