refactor(db): remove dummy includes

Former-commit-id: 6cf84f4b81e93c4a02ec7467b14e0ebc9227585d

cpp/src/db/DBImpl.cpp

@@ -2,14 +2,9 @@
 #include <chrono>
 #include <thread>
 #include <iostream>
-#include <faiss/IndexFlat.h>
-#include <faiss/MetaIndexes.h>
-#include <faiss/index_io.h>
-#include <faiss/AutoTune.h>
 #include <cstring>
 #include <wrapper/Topk.h>
 #include <easylogging++.h>
-#include <wrapper/IndexBuilder.h>
 #include <cache/CpuCacheMgr.h>
 
 #include "DBImpl.h"

cpp/src/db/MemManager.cpp

 #include <iostream>
 #include <sstream>
 #include <thread>
-
 #include <easylogging++.h>
 
 #include "MemManager.h"