Add "Old-" prefix to "Version" header in some cases

Add "Old-" prefix to "Version" header in some cases

These version numbers are historical accidents and not relevant today.
Ref: https://lists.gnu.org/r/emacs-devel/2020-03/msg00080.html

* lisp/calendar/icalendar.el:
* lisp/emacs-lisp/checkdoc.el:
* lisp/hippie-exp.el:
* lisp/linum.el:
* lisp/master.el:
* lisp/progmodes/cwarn.el:
* lisp/repeat.el:
* lisp/ruler-mode.el:
* lisp/textmodes/remember.el:
* lisp/wdired.el:
* lisp/woman.el: Change "Version" header to "Old-Version".