s3:lib/events: use DLIST_DEMOTE() for fd events

s3:lib/events: use DLIST_DEMOTE() for fd events

This makes sure that fd events doesn't dry out,
because a fd with a lower number is busy.

metze

The last 3 patches address bug #7942 (inotify can somehow cause endless loops in
with select()).

Autobuild-User: Stefan Metzmacher <metze@samba.org>
Autobuild-Date: Mon Jan 31 16:59:44 CET 2011 on sn-devel-104
(cherry picked from commit ad10289ebcc78ab62ec86abb29f81eb769d17f4e)
(cherry picked from commit 3d2f72844a221dbdfe94fbf6e2b45c98ee158a9b)
(cherry picked from commit 44a2e73cf07110e463f2262c50a377bdf17253d6)