Fix potential heap corruption in "gpg -v --version".

* g10/gpg.c (build_list): Rewrite to cope with buffer overflow in
certain locales.

This fixes an obvious bug in locales where the translated string is
longer than the original. The bug could be exhibited by using
LANG=ru_RU.utf8 gpg -v --version.

En passant we also removed the trailing white space on continued
lines.

(cherry picked from commit e33e74e3a4b2b4a0341f933410ddd5db7a12515e)

Note that this version uses utf8_charcount to get the indentation
mostly right.

• Reported-by: Dmitry V. Levin" <ldv at altlinux.org>
• Signed-off-by: Werner Koch <wk@gnupg.org>