schannel: restore debug message in schannel_connect_step2

This is a follow-up to recent commit 2218c3a which removed the debug
message to avoid an unused variable warning. The message has been
reworked to avoid the warning.

Ref: #8320 (comment)

Closes #8336

lib/vtls/schannel.c

@@ -1037,6 +1037,10 @@ schannel_connect_step2(struct Curl_easy *data, struct connectdata *conn,
 
   doread = (connssl->connecting_state != ssl_connect_2_writing) ? TRUE : FALSE;
 
+  DEBUGF(infof(data,
+               "schannel: SSL/TLS connection with %s port %hu (step 2/3)",
+               SSL_HOST_NAME(), conn->remote_port));
+
   if(!backend->cred || !backend->ctxt)
     return CURLE_SSL_CONNECT_ERROR;