On commit ee2c645c "Make sure we don't create the file twice"

[Ivan Shapovalov]

Hi Aleix (and probably others),

I've changed my mind on whether we shall do the "create file, then scan for 
items": this is apparently a race between our thread and an inotify/whatever 
thread in QFileSystemWatcher backend.
So maybe we can just temporarily block watcher's signals before creating file 
and manually call dirtyFile() for the parent directory?

Cheers,
Ivan