mq/qqueue: add --purge option to delete a queue and its patch dir qqueue --delete only deletes the reference to the queue, and leaves the associated patch directory behind. There is no Mercurial-way of getting rid of that patch directory afterward. This patch adds the --purge option to qqueue, that deletes the queue from the list, and also removes the associated patch dir. If the queue was non-existant, but the patch dir was, it is removed nonetheless. This is to avoid manual intervention in the .hg directory.