This is a partial reversion of #9728, and should fix #10612.

9728 used the AWS instance id as the node name.  But proxy, logs
and exec all used the node name as the host name for contacting the minion.

It is possible to resolve a host to the IP, and this fixes logs.  But
exec and proxy also require an SSL certificate match on the hostname,
and this is harder to fix.

So the sensible fix seems to be a minimal reversion of the changes in #9728,
and we can revisit this post 1.0.