remote file creation: use parent folder's mtime instead of current time

[nil0x42]

parent directory of altered files needs to have mtime restored too

[nil0x42]

UPDATE:
The real problem is about creating new files.

When a new file is created in a parent folder, the parent folder's mtime will be immediately altered.
So, to improve stealth, when creating a new file, parent folder's mtime should be used instead of current mtime.

If the file is removed by us later, we're then keeping no traces of our actions.