Upstream commit d807e289db96 no long set IFF_UP flag as it is considered
administrative only in OpenBSD and NetBSD. However, FreeBSD uses this
flag. Reinstate setting this flag based on interface status.
This commit also reverts 5fcdc19a8111 (and the subsequent 116679b39cb9
sleep removal) as they are no longer needed.
The upstream commit is based only on OpenBSD testing was assumed to work on NetBSD and FreeBSD too.
This patch is something we can start discussing with our upstream about. Even if they reject this change it allows us to build upon future revisions without significant merge conflicts.