bug#10802: rmdir -p behaviour

[Paul Ruane]

Hi,

If I have the following directory structure:

> mkdir -p a/a1 a/a2

If I then remove these empty directories using the --parents option,
rmdir reports an error:

> rmdir --parents a/a1 a/a2
rmdir: failed to remove directory `a': Directory not empty

Despite the error, the command completes with the desired result.

It is pretty obvious what is happening: rmdir is treating each
argument in isolation:

1. argument 'a/a1'
    1.1. attempt to remove 'a/a1': success
    1.2. attempt to remove 'a': error as directory not empty
2. argument 'a/a2'
    2.1. attempt to remove 'a/a2': success
    2.2. attempt to remove 'a': success

However I would expect the parent directory removal to happen after
the arguments are removed, which would result in a better user
experience. For example:

1. argument 'a/a1'
    1.1. attempt to remove 'a/a1': success
    1.2. remember parent 'a'
2. argument 'a/a2'
    2.1. attempt to remove 'a/a2': success
    2.2. parent 'a' already in set of parents
3. remembered parent 'a'
    3.1. remove parent 'a': success

Many thanks,
Paul.