fix cpp session compilation

Author: hongzhi-gao

example/client-cpp-example/src/TableModelSessionExample.cpp

@@ -22,7 +22,7 @@
 
 using namespace std;
 
-TableSession *session;
+shared_ptr<TableSession> session;
 
 void insertRelationalTablet() {
 
@@ -203,8 +203,6 @@ int main() {
         cout << "session close\n" << endl;
         session->close();
 
-        delete session;
-
         cout << "finished!\n" << endl;
     } catch (IoTDBConnectionException &e) {
         cout << e.what() << endl;