A snapshot is something that reflects the state of something at a
certain point in time.  It does not change.

The file our snapshot commands create (or the node they install) is not
a snapshot, as it does change over time.  It is an overlay.  We cannot
do anything about the parameter names, but we can at least adjust the
descriptions to reflect that fact.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-id: 20190603202236.1342-2-mreitz@redhat.com
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NMax Reitz <mreitz@redhat.com>