[clang-move] The new.cc file should include new_header.h instead of old_header.h

Summary:
Previously, all #includes (includeing old_header.h) in old.cc will be copied to new.cc,
however, the new.cc should include new_header.h instead of the old_header.h

Before applying the patch, the new.cc looks like:

```
#include "old_header.h"
...
```

The new.cc looks like with this patch:

```
#include "new_header"
...
```

Reviewers: ioeric

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D24828

llvm-svn: 282247