Check return values in ssl_print_tmp_key()

Check return values in ssl_print_tmp_key()

Use EVP_PKEY_get0_EC_KEY() instead of the get1 version to avoid an
EVP_PKEY_free(). Check return values: if either EVP_PKEY_get0_EC_KEY()
or EC_KEY_get0_group() fail, a NULL dereference occurs.

CID 43289

ok jsing