startup-tags: Pull startup-tags from sysinit.target

- Make startup-tags a dependency of sysinit-target

    WantedBy=sysinit.target
    Before=sysinit.target

Note, that while a Wants= idependency in a .target unit would imimply a
After= order dependency, this does not apply to dependencies created via
from WantedBy, so we have to specify the order explicitly.

- Disable default dependencies for this service unit, because service
  units have a default dependency on sysinit.target and we can't wait
  for ourself.

    DefaultDependencies=no

- Wait for the root device remounted read/write, so that we can populate
  /node

    After=systemd-remount-fs.service

With this change, we no longer need to create an explicit dependency to
this unit in conditionally started service or socket units, because these units
have a default order dependency on sysinit.target and the later
basic.target.

misc_systemd_units/startup-tags.service

@@ -1,7 +1,15 @@
 [Unit]
 
+DefaultDependencies=no
+After=systemd-remount-fs.service
+Before=sysinit.target
+
 [Service]
+
 Type=oneshot
 RemainAfterExit=yes
 ExecStart=/usr/sbin/hostconfig --populate-node
 
+[Install]
+
+WantedBy=sysinit.target