core: OOM really shouldn't be considered a deserialization parse failure
update TODO
manager: log deserialization errors only at LOG_DEBUG level

During upgrades and when transitioning between different systemd
versions in initrd and on the host we have to expect that some
serialization fields are unknown or parse incorrectly. This shouldn't
really be considered an error, hence downgrade the log messages about
it to debug. This way we can still trace it, but it doesn't confuse
users.

This kinda reverts 46849c3f.
systemctl: show unit file preset state in "systemctl status" output"
busctl: fix 'command line' style output of properties
bus-proxy: don't log bus policy every single time we run
rc-local: drop SysVStartPriority= field which is now obsolete
update TODO
shared: add format helpers for printing MAC addresses

Use these in networctl.
DISTRO_PORTING: add full path for /usr/lib/systemd/systemd and fix grammar

(David: fixed up some trailing whitespace and commit-message)
networkd: Introduce Link Layer Discovery Protocol (LLDP)

This patch introduces LLDP support to networkd. it implements the
receiver side of the protocol.

The Link Layer Discovery Protocol (LLDP) is an industry-standard,
vendor-neutral method to allow networked devices to advertise
capabilities, identity, and other information onto a LAN. The Layer 2
protocol, detailed in IEEE 802.1AB-2005.LLDP allows network devices
that operate at the lower layers of a protocol stack (such as
Layer 2 bridges and switches) to learn some of the capabilities
and characteristics of LAN devices available to higher
layer protocols.
networkd: integrate LLDP

This patch integrates LLDP with networkd.

Example conf:
file : lldp.network

[Match]
Name=em1

[Network]
LLDP=yes
lldp: fix memory leak

Fix couple of memory leaks
LLDP: rename log
LLDP: remove assert