Bug#760614: Mention where snapshots end up

[積丹尼 Dan Jacobson]

Package: systemd
Version: 214-1
Severity: wishlist
File: /usr/share/man/man1/systemctl.1.gz

# systemctl snapshot
snapshot-1.snapshot
# ls
#

Mention on the man page,
and when running the command,
where the file ends up.

Indeed it is not even mentioned on
# man systemd.snapshot




Or at least add a command that will then copy in-and-out a snapshot to
somewhere the user can examine it.

And / or mention if it indeed is not a file in fact at all.