Remove all saved data for specified GP during start new race.

Generally it shouldn't happen because the rule is one save per one GP, but it is possible with old config.xml files.

src/race/race_manager.cpp

@@ -376,18 +376,26 @@ void RaceManager::startNew(bool from_overworld)
         init_gp_rank ++;
     }
 
-    m_track_number = 0;
     if (m_major_mode == MAJOR_MODE_GRAND_PRIX)
     {
         if (m_continue_saved_gp)
         {
-            m_track_number  = m_saved_gp->getNextTrack();
+            m_track_number = m_saved_gp->getNextTrack();
             m_saved_gp->loadKarts(m_kart_status);
         }
-        else if (m_saved_gp != NULL)
+        else 
         {
-            m_saved_gp->remove();
-            m_saved_gp = NULL;
+            m_track_number = 0;
+            while (m_saved_gp != NULL)
+            {
+                m_saved_gp->remove();
+                m_saved_gp = SavedGrandPrix::getSavedGP(
+                                             StateManager::get()
+                                             ->getActivePlayerProfile(0)
+                                             ->getUniqueID(),
+                                             m_grand_prix.getId(),
+                                             m_player_karts.size());
+            }
         }
     }