Update LLVM for 3.5 rebase (r209712).

Change-Id: I149556c940fb7dc92d075273c87ff584f400941f
diff --git a/tools/bugpoint/bugpoint.cpp b/tools/bugpoint/bugpoint.cpp
index 5c03b41..c7dae0f 100644
--- a/tools/bugpoint/bugpoint.cpp
+++ b/tools/bugpoint/bugpoint.cpp
@@ -99,7 +99,7 @@
   class AddToDriver : public FunctionPassManager {
     BugDriver &D;
   public:
-    AddToDriver(BugDriver &_D) : FunctionPassManager(0), D(_D) {}
+    AddToDriver(BugDriver &_D) : FunctionPassManager(nullptr), D(_D) {}
 
     void add(Pass *P) override {
       const void *ID = P->getPassID();