verify_hostname should be set false when it donsn't need

to suppress the warning.

```
warning: verify_hostname requires hostname to be set
```

Signed-off-by: Yuta Iwama <ganmacs@gmail.com>

lib/fluent/plugin_helper/socket.rb

@@ -145,7 +145,7 @@ def socket_create_tls(
           context.ciphers = ciphers
           context.verify_mode = OpenSSL::SSL::VERIFY_PEER
           context.cert_store = cert_store
-          context.verify_hostname = true if verify_fqdn && fqdn
+          context.verify_hostname = verify_fqdn && fqdn
           context.key = OpenSSL::PKey::read(File.read(private_key_path), private_key_passphrase) if private_key_path
 
           if cert_path