L4sys: build fix

experiment.hpp is parsed before l4sys.ph.h is generated
-> remove dependency

Change-Id: I128108e562877caca732ad43fdb65b12e56951f8

src/experiments/l4-sys/experiment.hpp

@@ -8,7 +8,8 @@
 #include "util/Logger.hpp"
 #include "sal/Listener.hpp"
 
-#include "l4sys.pb.h"
+//#include "l4sys.pb.h"
+struct L4SysProtoMsg_Result;
 
 class L4SysExperimentData;