darwinssl: Turning off host validation does turn off SNI
schannel: Turning off host validation does not turn off SNI. However, SNI
is not available which SChannel on Windows XP machines, regardless of the
host validation setting.
- Remove the SNI disabled when host verification disabled message
since that is incorrect.
- Show a message for legacy versions of Windows <= XP that connections
may fail since those versions of WinSSL lack SNI, algorithms, etc.
In DarwinSSL the SSLSetPeerDomainName function is used to enable both
sending SNI and verifying the host. When host verification is disabled
the function cannot be called, therefore SNI is disabled as well.