In OpenSSL pre 1.1.0, 'openssl x509 -keyform engine' was possible
and supported. In 1.1.0, type of keyform argument is OPT_FMT_PEMDER
which doesn't support engine. This changes type of keyform argument
to OPT_FMT_PDE which means PEM, DER or engine and updates the manpage
including keyform and CAkeyform.
This restores the pre 1.1.0 behavior.
This issue is very similar than https://github.com/openssl/openssl/issues/4366
Reviewed-by: Dmitry Belyavskiy <firstname.lastname@example.org>
Reviewed-by: Matt Caswell <email@example.com>
Reviewed-by: Richard Levitte <firstname.lastname@example.org>
(Merged from https://github.com/openssl/openssl/pull/10609)