Use XMPP service name when creating the TLS socket

instead of the hostname. This should make SNI also to use the XMPP
service name instead of the hostname.

Fixes SMACK-813.

smack-tcp/src/main/java/org/jivesoftware/smack/tcp/XMPPTCPConnection.java

@@ -795,7 +795,7 @@ public class XMPPTCPConnection extends AbstractXMPPConnection {
         Socket plain = socket;
         // Secure the plain connection
         socket = context.getSocketFactory().createSocket(plain,
-                host, plain.getPort(), true);
+                config.getXMPPServiceDomain().toString(), plain.getPort(), true);
 
         final SSLSocket sslSocket = (SSLSocket) socket;
         // Immediately set the enabled SSL protocols and ciphers. See SMACK-712 why this is