bus: when we are connected to a bus, then do not assume peer creds are useful as message creds
bus: when getting a kdbus connection into a container wait first for child, then read message

There's no EOF generated for AF_UNIX/SOCK_DGRAM sockets, hence let's
wait for the child first to see if it succeeded, only then read the socket.
bus: update kdbus.h
bus-proxyd: init cleanup variable
machinectl: fix success check when getting pty from within container
sd-event: fix return code of sd_event_run()
units: limit caps for bus proxyd and driverd services
units: systemd-machined now exits on idle and we shouldn't try to restart it then
core: when we close the notify fd, we also need to free its event source
sd-event: make sd_event_add_signal() fail with EBUSY if signal is not blocked
bus: fix sender match creation on kdbus
bus: don't attach KDBUS_ITEM_ID to match ioctl() if we don't need it
bus: fix assert when serializing fixed size struct to gvariant
update TODO
bus: allow peeking signatures recusively inside of containers

Previously we invalidated the peeked signature as soon as the caller
would recurse into a container, making stack based handling difficult.
With this change we will keep the peeked signature around until the user
advances to the next field.
hwdb: Add SDIO product ID for Marvell SD8897 WLAN function