Added protection against zero-length files in scheduler.

scheduler/Scheduler.cpp

@@ -122,6 +122,9 @@ void Scheduler::queueArchiveWithGivenId(const uint64_t archiveFileId, const std:
   cta::utils::Timer t;
   using utils::postEllipsis;
   using utils::midEllipsis;
+  
+  if (!request.fileSize)
+    throw cta::exception::Exception("Rejecting archive request for zero-length file.");
 
   const auto queueCriteria = m_catalogue.getArchiveFileQueueCriteria(instanceName, request.storageClass,
     request.requester);