Remove DataHandle::commit()

From discussion with @leggett on !462 (merged), it seems like the DataHandle::commit() functionality is not used, and that using it is not envisioned anymore. I would thus tentatively propose to remove it.

Can you try this commit in your respective experiment frameworks and tell me how well it goes?

GaudiHive/src/AlgoExecutionTask.cpp

@@ -55,8 +55,10 @@ tbb::task* AlgoExecutionTask::execute()
     eventfailed = true;
   }
 
+#if defined( GAUDI_V30_DATAHANDLE_COMMIT )
   // Commit all DataHandles
   this_algo->commitHandles();
+#endif
 
   // DP it is important to propagate the failure of an event.
   // We need to stop execution when this happens so that execute run can