Assuming you're not worried about it not being available because the file is missing/in error
This will bypass the error and allow you to continue loading.
Require instead of load
cedet-devel-load.el on https://github.com/emacsmirror/cedet/blob/master/cedet-devel-load.el the last line is
This means you can replace your load line with:
;; If you haven't already added it to load path above
(add-to-list 'load-path "~/.emacs.d/cedet")
This will use the library and ensure you do not have to worry about it being loaded more than the initial time.