OpenSSL: acknowledge CURLOPT_SSL_VERIFYHOST without VERIFYPEER

Setting only CURLOPT_SSL_VERIFYHOST without CURLOPT_SSL_VERIFYPEER set
should still verify that the host name fields in the server certificate
is fine or return failure.

Bug: http://curl.haxx.se/mail/lib-2013-10/0002.html
Reported-by: Ishan SinghLevett