rails/rails — pull request #10627 by vipulnsward (2013-05-15 05:06:59+00:00)
Title: change to destructive `deep_symbolize_keys` 

change to destructive `deep_symbolize_keys` after https://github.com/rails/rails/commit/df24b8790f22384a068fece7042f04ffd2fcb33e which allows to do so.
This helps to avoid extra hash object creation, by symbolizing inplace