units: order sysinit.target, debug-shell.service after systemd-vconsole-setup

Previous patch to add an implicit dependency effectively orders various getty
services after systemd-vconsole-setup.service. But I think it's cleaner to also
order the service before sysinit.target, like it was before
8125e8d38e. There might be units which don't do
use TTYVHangup= but would like to have the console fully initialized.

Also, add a manual ordering to debug-shell.service, because it has
ImplicitDependencies=no. This might delay debug-shell.service a bit, but
systemd-vconsole-setup.service has no dependencies and should be very quick, so
this should not be noticable in practice. Without the ordering, the terminal
might not have a key map loaded, making debug-shell.service hard to use.

units/debug-shell.service.in

@@ -13,6 +13,7 @@ Documentation=man:systemd-debug-generator(8)
 DefaultDependencies=no
 IgnoreOnIsolate=yes
 ConditionPathExists={{DEBUGTTY}}
+After=systemd-vconsole-setup.service
 
 [Service]
 Environment=TERM=linux

units/systemd-vconsole-setup.service.in

@@ -11,6 +11,7 @@
 Description=Setup Virtual Console
 Documentation=man:systemd-vconsole-setup.service(8) man:vconsole.conf(5)
 DefaultDependencies=no
+Before=sysinit.target
 Before=initrd-switch-root.target shutdown.target
 ConditionPathExists=/dev/tty0