[RFR] 8214440: ldap over a TLS connection negotiate failed with "javax.net.ssl.SSLPeerUnverifiedException: hostname of the server '' does not match the hostname in the server's certificate"

[Rob McKenna]

Hi folks,

I'd like to fix this test failure caused by 8160768.

The problem is that the LdapDnsProviderResult sets the hostname to the
empty String and gets passed to StartTlsResponseImpl.verify.
Unfortunately StartTlsResponseImpl.verify only expects null values.
Since null and the empty String are functionally equivalent I've added a
check to StartTlsResponseImpl.verify to take the empty String into
account.

http://cr.openjdk.java.net/~robm/8214440/webrev.01/

This was caught by an existing test which I managed to miss in my
testing incantation.

    -Rob