* lisp/whitespace.el: Fix double evaluation.

* lisp/whitespace.el: Fix double evaluation.
(whitespace-space, whitespace-hspace, whitespace-tab)
(whitespace-newline, whitespace-trailing, whitespace-line)
(whitespace-space-before-tab, whitespace-indentation)
(whitespace-empty, whitespace-space-after-tab): Turn defcustoms into
obsolete defvars.
(whitespace-hspace-regexp): Fix regexp for emacs-unicode.
(whitespace-color-on): Use a single font-lock-add-keywords call.
Fix double-evaluation of face variables.