Remove redundant requires of easymenu

Remove redundant requires of easymenu

* lisp/allout.el:
* lisp/emacs-lisp/edebug.el:
* lisp/emacs-lisp/ert.el:
* lisp/erc/erc-menu.el:
* lisp/help-mode.el:
* lisp/net/dictionary.el:
* lisp/nxml/rng-nxml.el:
* lisp/progmodes/ebrowse.el:
* lisp/progmodes/meta-mode.el:
* lisp/progmodes/prolog.el:
* lisp/progmodes/ps-mode.el:
* lisp/progmodes/vera-mode.el:
* lisp/wid-browse.el: Remove redundant require of easymenu.  We only
use the autoloaded macro 'easy-menu-define' here.