APPS: Fix 'openssl dhparam'
APPS: Fix 'openssl dhparam'

'dhparam' can't be completely rewritten in terms of EVP_PKEY functions
yet, because we lack X9.42 support.  However, we do when generating,
but forgot to extract a DH pointer with EVP_PKEY_get0_DH().

Reviewed-by: David von Oheimb <fbbca6c63636e78e7034aaf1b4aa3a9736383192@siemens.com>
(Merged from https://github.com/openssl/openssl/pull/12048)

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl