Make Curl_schannel_version() return "WinSSL"

Modification based on voting result:

http://curl.haxx.se/mail/lib-2012-07/0104.html

lib/curl_schannel.c

@@ -1166,7 +1166,7 @@ void Curl_schannel_cleanup(void)
 
 size_t Curl_schannel_version(char *buffer, size_t size)
 {
-  size = snprintf(buffer, size, "SSL-Windows-native");
+  size = snprintf(buffer, size, "WinSSL");
 
   return size;
 }