[v3] Use locale cache for boolean names

[Benjamin Kosnik]

>This can also go onto 3.3 if the locale cache
>backport is approved.
>
>2003-03-03  Jerry Quinn  <jlquinn@optonline.net>
>        * include/bits/locale_facet.tcc
>(num_put::do_put(bool)):
>        Use locale cache for truename and falsename.

looks great, fine for both

-benjamin