Comment 1 for bug 1475749

This appears to be an issue with the patches to shadow for subuid/subgid support. The --{add,del}-sub{uid,gid}s options don't operate on /etc/passwd, only on /etc/sub{uid,gid}; but the code causes usermod to fail if called for any non-local user.

Assuming there's no policy reason why non-local users are disallowed from /etc/sub{uid,gid}, this is a simple fix. Cc:ing Serge Hallyn for comment, as he originally pulled these patches in.