[Clang] 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.

Differential revision: https://reviews.llvm.org/D66259

llvm-svn: 368942
diff --git a/clang/lib/Driver/ToolChains/BareMetal.cpp b/clang/lib/Driver/ToolChains/BareMetal.cpp
index 1544727..dff0e04 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.cpp
+++ b/clang/lib/Driver/ToolChains/BareMetal.cpp
@@ -191,7 +191,7 @@
   CmdArgs.push_back("-o");
   CmdArgs.push_back(Output.getFilename());
 
-  C.addCommand(llvm::make_unique<Command>(JA, *this,
+  C.addCommand(std::make_unique<Command>(JA, *this,
                                           Args.MakeArgString(TC.GetLinkerPath()),
                                           CmdArgs, Inputs));
 }