man: fix links to systemd-efi-boot-generator(8)
man: /usr/bin may contain binaries in any compatible arch, not just the primary one
sd-bus: support connecting to remote hosts, directly into containers

systemctl -H root@foobar:waldi

will now show a list of services running on container "waldi" on host
"foobar", using "root" for authenticating at "foobar".

Since entereing a container requires priviliges, this will only work
correctly for root logins.
bus: close a bus that failed to connect
sd-login: use the same code for verfiying machine names everywhere