Test directory delete

In order to move the top level directory, first
it was necessary to check that the empty directory
would be removed from disk.
Move dir deletion into prep_directory
NB: improve callback/handle closing in submit

There are a number of error conditions where
neither the handle nor the callback object
from client.submit() will be returned to the
user. Since the exceptions do not include the
objects and it was not a part of the "API" to
require a `close()` we will make a best effort
at cleaning up resources when an exception
occurs.
Include only dir and log in tomove
Fix test_fs after changes to get_fileset