PFW: Fix the useless subsystem resync on PFW load

BZ: 97808

The PFW used to resynchronise some subsystems at start before
back/forward syncronisation. Which was useless.

Reset subsystems 'needToResync' flag during PFW start before sync to
avoid this dummy resync.

Change-Id: Id0c0bb786f10e2724222fc18f2085164e95f963f
Signed-off-by: Kevin Rocard <kevinx.rocard@intel.com>
Reviewed-on: http://android.intel.com:8080/98452
Reviewed-by: cactus <cactus@intel.com>
Reviewed-by: Denneulin, Guillaume <guillaume.denneulin@intel.com>
Reviewed-by: De Chivre, Renaud <renaud.de.chivre@intel.com>
Tested-by: Dixon, CharlesX <charlesx.dixon@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>
diff --git a/parameter/SystemClass.h b/parameter/SystemClass.h
index a522a33..5bc9006 100644
--- a/parameter/SystemClass.h
+++ b/parameter/SystemClass.h
@@ -41,9 +41,20 @@
     // Subsystem factory
     const CSubsystemLibrary* getSubsystemLibrary() const;
 
-    // Fill syncer-set with syncers from subsytems that need resync
+    /**
+      * Look for subsystems that need to be resynchronized.
+      * Consume the need to be resynchronized
+      * and fill a syncer set with all syncers that need to be resynchronized
+      *
+      * @param[out] syncerSet The syncer set to fill
+      */
     void checkForSubsystemsToResync(CSyncerSet& syncerSet);
 
+    /**
+      * Reset subsystems need to resync flag.
+      */
+    void cleanSubsystemsNeedToResync();
+
     // base
     virtual bool init(string& strError);
     virtual string getKind() const;