Remove reopen-buffer.

revert-buffer does the trick. See
http://www.masteringemacs.org/articles/2014/02/28/my-emacs-keybindings/
for a fancier version and keybinding.
Add kill-this-buffer function and keybinding.

Oh, so handy. Via
http://www.masteringemacs.org/articles/2014/02/28/my-emacs-keybindings/.