small bug in last commit

Hey. That was my first pull request - didn't realise it would happen so quickly.

Tested my previous commit and it doesn't move directories with trailing slashes properly - if you do hadoop fs -mv /a/b/c /d/e/g/ it will move c so that you end up with /d/e/f/c/. I changed what i'd written so that that never happens on atomic writes, and instead you get /d/e/c as the result.

Also confirmed that without trailing slashes it works as before.