[Libguestfs] [PATCH INCOMPLETE] daemon: Reimplement LVM filters using lvmdevices command

LVM2 managed to break device filters. This patch attempts a fix. https://bugzilla.redhat.com/show_bug.cgi?id=1965941 However it is not working, because the new "lvmdevices" command which is supposed to be used to set the new filters does not work for partitioned whole devices. As far as I can tell there is no way to emulate the old behaviour of filtering such a device. (Adding filters for each partition in the device is one possible workaround, but the filters will be out of date as soon as a new partition is created on the device.) While I investigate this, I'm posting the patch FYI. Rich.