Most images won't work without multiple ids/gids. Error out
immediately if there are no multiple ids available.
The error code when the user is not present in /etc/sub{g,u}id looks
like:
$ bin/podman run --rm -ti alpine echo hello
ERRO[0000] No subuid ranges found for user "gscrivano"
Closes: https://github.com/projectatomic/libpod/issues/1087
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Closes: #1097
Approved by: rhatdan