r20442: Slight rewrite of the change notify infrastructure. This now survives the

r20442: Slight rewrite of the change notify infrastructure. This now survives the
first of the raw-notify subtests, the one-level test_notify_dir without any
flags around yet.

The tricky part was getting the data structures right, I hope the next tests
don't let that fall over.

fsp->notify is now by default NULL, meaning that nobody has issued a
changenotify call. This means nobody is interested in changes for this
directory.

If that has happened, notify_change_buf collects the changes if no current
request is outstanding, and it collects the requests if no change has happened
since the last request.

Happy New Year, somewhere on this planet it's already 2007 :-)

Volker

P.S: Jeremy, there's a question for you in smbd/files.c line 367.
(This used to be commit ce0ad24988075465addcac0b9afc872e909135af)