fix unit test error in chunkserver_clone_recover.cpp

new clone and snapshot write will return success
fix unit test to compatiable with the old clone and snapshot version
fix statics for the chunk file count

add snapshot and clone support for the old version below release1.5

src/chunkserver/datastore/chunkserver_chunkfile_v2.cpp

@@ -93,16 +93,6 @@ CSChunkFile_V2::CSChunkFile_V2(std::shared_ptr<LocalFileSystem> lfs,
 }
 
 CSChunkFile_V2::~CSChunkFile_V2() {
-    if (fd_ >= 0) {
-        lfs_->Close(fd_);
-    }
-
-    if (metric_ != nullptr) {
-        metric_->chunkFileCount << -1;
-        if (isCloneChunk_) {
-            metric_->cloneChunkCount << -1;
-        }
-    }
 }
 
 CSErrorCode CSChunkFile_V2::Open(bool createFile) {