[C++11] Replace llvm::next and llvm::prior with std::next and std::prev.

Remove the old functions.

llvm-svn: 202636
diff --git a/llvm/lib/CodeGen/StackProtector.cpp b/llvm/lib/CodeGen/StackProtector.cpp
index 349b733..4a3487c 100644
--- a/llvm/lib/CodeGen/StackProtector.cpp
+++ b/llvm/lib/CodeGen/StackProtector.cpp
@@ -284,8 +284,7 @@
   const unsigned MaxSearch = 4;
   bool NoInterposingChain = true;
 
-  for (BasicBlock::reverse_iterator I = llvm::next(BB->rbegin()),
-                                    E = BB->rend();
+  for (BasicBlock::reverse_iterator I = std::next(BB->rbegin()), E = BB->rend();
        I != E && SearchCounter < MaxSearch; ++I) {
     Instruction *Inst = &*I;