[llvm] r185832 - Create files with the correct permission instead of changing it afterwards.

[Rafael Espíndola]

> I'm not sure I understand. The code calls close(FD) at the end of the
> function, so presumably the raw_fd_ostream could just be moved out of the
> block it is currently in?

The destructor will flush buffers, which I think will change the last
modified time. That is why I want to first destroy the stream, then
set the last modification time then close the file descriptor. I will
try factoring the calls to open (and the flags raw_fd_ostream
currently uses) and see what it looks like.

> -- Sean Silva

Cheers,
Rafael