[llvm] Migrate llvm::make_unique to std::make_unique

Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

llvm-svn: 369013
diff --git a/llvm/tools/llvm-elfabi/ELFObjHandler.cpp b/llvm/tools/llvm-elfabi/ELFObjHandler.cpp
index a41fc19..b886a8d 100644
--- a/llvm/tools/llvm-elfabi/ELFObjHandler.cpp
+++ b/llvm/tools/llvm-elfabi/ELFObjHandler.cpp
@@ -292,7 +292,7 @@
   using Elf_Phdr_Range = typename ELFT::PhdrRange;
   using Elf_Sym_Range = typename ELFT::SymRange;
   using Elf_Sym = typename ELFT::Sym;
-  std::unique_ptr<ELFStub> DestStub = make_unique<ELFStub>();
+  std::unique_ptr<ELFStub> DestStub = std::make_unique<ELFStub>();
   const ELFFile<ELFT> *ElfFile = ElfObj.getELFFile();
   // Fetch .dynamic table.
   Expected<Elf_Dyn_Range> DynTable = ElfFile->dynamicEntries();