Remove some more XEmacs compat code from viper*.el

Remove some more XEmacs compat code from viper*.el

* lisp/emulation/viper-ex.el (viper-ex-read-file-name): Ditto.

* lisp/emulation/viper-init.el (viper-ms-style-os-p)
(viper-has-face-support-p, viper-deactivate-input-method)
(viper-activate-input-method, viper-set-input-method): Ditto.

* lisp/emulation/viper-util.el
(viper-get-saved-cursor-color-in-replace-mode)
(viper-get-saved-cursor-color-in-insert-mode)
(viper-get-saved-cursor-color-in-emacs-mode)
(viper-set-replace-overlay, viper-key-to-emacs-key)
(viper-set-unread-command-events): Ditto.

* lisp/emulation/viper.el (viper-go-away, viper-set-hooks)
(viper-non-hook-settings): Remove XEmacs compat code.