Comment out old Google Translate support and as such remove the need for JSON.

Note that on standalone, json headers are installed in json/,
no idea why in the packages this isn't the case... But anyway,
it isn't used at all anymore now so it doesn't really matter.

I didn't remove the json package for non-standalone and the
downloading thereof... (I can't test non-standalone).

indra/newview/lltranslate.h

@@ -35,7 +35,7 @@
 
 #include "llhttpclient.h"
 #include "llbufferstream.h"
-#include "jsoncpp/reader.h"
+#include "json/reader.h"
 
 class LLTranslate
 {