Reject inappropriate private key encryption ciphers.
Reject inappropriate private key encryption ciphers.

The traditional private key encryption algorithm doesn't function
properly if the IV length of the cipher is zero. These ciphers
(e.g. ECB mode) are not suitable for private key encryption
anyway.

Reviewed-by: Emilia Käsper <6521fc25e7624eef7c3a0d89b71de7e612d27d37@openssl.org>

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