Fix coding style in apps/passwd file

Reformat some indents and braces based on OpenSSL coding style spec.

Signed-off-by: Paul Yang <paulyang.inf@gmail.com>

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3586)