Replace OwningPtr with std::unique_ptr.

This compiles cleanly with lldb/lld/clang-tools-extra/llvm.

llvm-svn: 203279
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index bfe332b..4dc25e89 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1203,7 +1203,7 @@
     }
 
     // Build the pipeline for this file.
-    OwningPtr<Action> Current(new InputAction(*InputArg, InputType));
+    std::unique_ptr<Action> Current(new InputAction(*InputArg, InputType));
     for (SmallVectorImpl<phases::ID>::iterator
            i = PL.begin(), e = PL.end(); i != e; ++i) {
       phases::ID Phase = *i;