Fix build with Boost 1.79

Index: src/mongo/shell/shell_utils_extended.cpp
--- src/mongo/shell/shell_utils_extended.cpp.orig
+++ src/mongo/shell/shell_utils_extended.cpp
@@ -39,6 +39,7 @@
 #endif
 
 #include <boost/filesystem.hpp>
+#include <boost/filesystem/fstream.hpp>
 #include <fstream>
 
 #include "mongo/scripting/engine.h"
