[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

llvm/lib/Object/ELFObjectFile.cpp

@@ -63,7 +63,7 @@ createPtr(MemoryBufferRef Object) {
   auto Ret = ELFObjectFile<ELFT>::create(Object);
   if (Error E = Ret.takeError())
     return std::move(E);
-  return make_unique<ELFObjectFile<ELFT>>(std::move(*Ret));
+  return std::make_unique<ELFObjectFile<ELFT>>(std::move(*Ret));
 }
 
 Expected<std::unique_ptr<ObjectFile>>