As it was, if a user operated on a directory while at the same
time iterating over the directory, the directory objects could
fall out of sync. In the best case, files may be skipped while
removing everything in a file, in the worst case, a very poorly
timed directory relocate could be missed.
Simple fix is to add the same directory tracking that is currently
in use for files, at a small code+complexity cost.
Christopher Haster
bf78b09d37