Don't change default find-file behaviour

Currently, opening any file that is read-only and not owned by the
current user triggers a root login prompt. This occurs for viewing
system files (e.g /etc/fstab), built-in elisp
libraries (e.g. simple.el.gz) and simply viewing files owned by other
users on a shared system.

We can't assume that this is the behaviour users want, and changing
built-in functions without asking is surprising.

Fixes bbatsov#20.

crux.el

@@ -313,8 +313,6 @@ buffer is not visiting a file."
               (crux-file-owned-by-user-p buffer-file-name))
     (crux-find-alternate-file-as-root buffer-file-name)))
 
-(add-hook 'find-file-hook #'crux-reopen-as-root)
-
 (defun crux-insert-date ()
   "Insert a timestamp according to locale's date and time format."
   (interactive)