Emacs often changes the behavior suddenly and drastically. Recent surprise to me was that role of ctrl-j (newline and indent) and ctrl-m (newline) switched out of the blue. I don’t understand the developer’s sense of changing user interface of a multi-decade years old software. But luckily, emacs has very powerful customization ability.

Adding this line reverts the key bindings back.
(when (fboundp 'electric-indent-mode) (electric-indent-mode -1))

I appreciate this post
http://emacs.stackexchange.com/questions/5939/how-to-disable-auto-indentation-of-new-lines