Update zh-CN.yml

Devise 3.1 no longer signs the user automatically in after confirmation.

ruby on rails - Avoid sign-in after confirmation link click using devise gem? - Stack Overflow
http://stackoverflow.com/questions/18655334/avoid-sign-in-after-confirmation-link-click-using-devise-gem
Merge pull request #103 from beviz/patch-1

Update zh-CN.yml