fix storage cleanup deleting the newest file instead of the oldest (#384)

Author: wl2027

server/src/main/java/org/eclipse/jifa/server/repository/FileRepo.java

@@ -29,5 +29,5 @@ public interface FileRepo extends CrudRepository<FileEntity, Long> {
 
     Optional<FileEntity> findByUniqueName(String uniqueName);
 
-    Optional<FileEntity> findFirstByOrderByCreatedTimeDesc();
+    Optional<FileEntity> findFirstByOrderByCreatedTimeAsc();
 }

server/src/main/java/org/eclipse/jifa/server/service/impl/FileServiceImpl.java

@@ -304,7 +304,7 @@ public NamedResource handleDownloadRequest(long fileId) throws Throwable {
 
     @Override
     public void deleteOldestFile() {
-        Optional<FileEntity> optional = fileRepo.findFirstByOrderByCreatedTimeDesc();
+        Optional<FileEntity> optional = fileRepo.findFirstByOrderByCreatedTimeAsc();
         if (optional.isPresent()) {
             FileEntity file = optional.get();
             doDelete(file);