fix bug: file overlap when learning sstables
fix bug: file overlap when learning sstables

rDSN-Projects/rocksdb.replicated,rDSN-Projects/rocksdb.replicated,rDSN-Projects/rocksdb.replicated,rDSN-Projects/rocksdb.replicated,rDSN-Projects/rocksdb.replicated,rDSN-Projects/rocksdb.replicated,rDSN-Projects/rocksdb.replicated