Quoting @cgwalters:
Just uploading this as an RFC. Now I know reading the code that systemd says
`Welcome to $OS` as a generic thing, but my initial impression on seeing this
was that it was almost sarcastic =)
Let's say "You are in emergency mode" as a more neutral/less excited phrase.
This patch is based on #3556, but makes the same change for rescue mode.
In the same vein as commit ac59f0c12c which added
the --wait option to the emergency service, this patch makes sure that plymouth
has exited before entering into the rescue mode.