cosmetic: drei: replace #\Delete with #\Rubout
cosmetic: drei: replace #\Delete with #\Rubout

The latter is a standard name and should be present on all
implementations if at all (ECL had #\Del synonym for instance).

onixie/mcclim,slyrus/mcclim,onixie/mcclim,slyrus/mcclim,onixie/mcclim