A gateway host without a hive whose only swarm name is the store's UI no
longer waits for swarm-services-cert: its nginx carries the stream
passthrough to the store and must come up while the store is sealed. Until
the services leaf lands, hive-gateway-self-signed-cert installs a throwaway
self-signed pair on the default and swarm-services paths there; on a host
without a hive it never references the hive leaf.
A host without a hive also no longer mints the hive-leaf identity or
defaults the options pointing at it, and does not render the hive-domain
vhost, whose upstream is hive-c0re.
Refs #4588