samba-bgqd: Fix samba-bgqd with "clustering=yes"/"include=registry"

samba-bgqd: Fix samba-bgqd with "clustering=yes"/"include=registry"

With the above combination, some flavor of lp_load() already
initializes global_event_ctx, for which the closeall_except() later on
will happily close the epoll fd for. If we want to close all file
descriptors at startup, this must be the very first thing overall.

Can't really write a proper test for this with knownfail that is
removed with the fix, because if we have clustering+include=registry,
the whole clusteredmember environment does not even start up.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Sat Jul 31 16:58:41 UTC 2021 on sn-devel-184