s3:locking:brlock: let validate_lock_entries keep entries for disconnected servers...

s3:locking:brlock: let validate_lock_entries keep entries for disconnected servers in traverses

We should not remove locks of disconnected opens just like that.
When getting the byte range lock record for a newly connected file
handle, we still do the clean up, because in that situation,
disconnected entries are not valid any more.

Signed-off-by: Gregor Beck <gbeck@sernet.de>
Reviewed-by: Michael Adam <obnox@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>