Extend check for encrypted private keys: with OpenSSL versions prior to 1.0.0,
inf->x_pkey->dec_pkey is always non-NULL, so also look at inf->enc_data.

PR 54698.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1467593 13f79535-47bb-0310-9956-ffa450edef68