Turn info message from DHT groups into debug.

src/cache/dht_groups.cpp

@@ -10,7 +10,6 @@ using namespace ouinet;
 #define _DEBUG(...) LOG_DEBUG(_LOGPFX, __VA_ARGS__)
 #define _WARN(...)  LOG_WARN(_LOGPFX, __VA_ARGS__)
 #define _ERROR(...) LOG_ERROR(_LOGPFX, __VA_ARGS__)
-#define _INFO(...)  LOG_INFO(_LOGPFX, __VA_ARGS__)
 
 using asio::yield_context;
 namespace file_io = util::file_io;
@@ -185,7 +184,7 @@ void DhtGroups::add( const GroupName& group_name
                    , Cancel& cancel
                    , yield_context yield)
 {
-    _INFO("Adding: ", group_name, " -> ", item_name);
+    _DEBUG("Adding: ", group_name, " -> ", item_name);
     fs::path group_p = group_path(group_name);
 
     // Create the storage representation of the item in the group.