Don't decode a public key in X509_PUBKEY_get0(): that is handled when
the key is parsed using x509_pubkey_decode() instead.
Reviewed-by: Emilia Käsper <emilia@openssl.org>
Cache the decoded public key when an X509_PUBKEY structure is initially
parsed so no locking is required. Ignore any decode errors.
When an application calls X509_PUBKEY_get0() subsequently it will either
get the cached key or the decode operation will be repeated which will
return an appropriate error.
Reviewed-by: Rich Salz <rsalz@openssl.org>
