Fix for #3674 Can't `rm` containers when disk full

Rather than creating a new directory and moving it there before deleting that
new directory, just move the directory we intend to delete.

In the old way, the Mkdirall could fail, which meant that you couldn't delete
containers when the disk was full.

Tested.

Docker-DCO-1.1-Signed-off-by: Peter Waller p@pwaller.net (github: pwaller)

Fixes #3674

/cc @drj11