DatabaseExperiment: fix headers

 -  Add missing iomanip header: Without this one, Fail/gem5 does not
    compile.

 -  Remove unnecessary sal/bochs header: This seems to be a relic from
    when the DatabaseExperiment was Bochs-specific.

Change-Id: I91c991795c2c2e76359e9d11415f5119d225a4ab

src/core/efw/DatabaseExperiment.cc

 #include <iostream>
+#include <iomanip>
 #include <fstream>
 
 #include <stdlib.h>
@@ -9,7 +10,6 @@
 #include <google/protobuf/descriptor.h>
 #include <google/protobuf/message.h>
 #include "comm/DatabaseCampaignMessage.pb.h"
-#include "sal/bochs/BochsListener.hpp"
 #include <string>
 #include <vector>