See #4162 - Don't delay before deleting a file via SMB

So I was looking at issue #4162, and on my box I was seeing this
problem of the exploit failing to delete the payload in C:\Windows,
and the error was "Rex::Proto::SMB::Exceptions::NoReply The SMB
server did not reply to our request". I ended up removing the sleep(),
and that got it to function properly again. The box was a Win 7 SP1.

I also tested other Winodws boxes such as Win XP SP3, Windows Server
2008 SP2 and not having the sleep() doesn't seem to break anything.
So I don't even know why someone had to add the sleep() in the first
place.
Land #4208, psexec delay fix