Revert "machined: don't force terminate registered machines"

This reverts commit 206e7a5f7b.

We actually want to allow shutting down containers that use
RegisterMachine() rather than CreateMachine() to register their own
unit. It should be safe to do so, since the primary usecase for
RegisterMachine() are container managers that run only a single
container within their own unit, such as systemd-nspawn.

src/machine/machine.c

@@ -406,12 +406,10 @@ static int machine_stop_scope(Machine *m) {
         if (!m->unit)
                 return 0;
 
-        if (!m->registered) {
-                r = manager_stop_unit(m->manager, m->unit, &error, &job);
-                if (r < 0) {
-                        log_error("Failed to stop machine scope: %s", bus_error_message(&error, r));
-                        return r;
-                }
+        r = manager_stop_unit(m->manager, m->unit, &error, &job);
+        if (r < 0) {
+                log_error("Failed to stop machine scope: %s", bus_error_message(&error, r));
+                return r;
         }
 
         free(m->scope_job);

src/machine/machine.h

@@ -72,7 +72,6 @@ struct Machine {
 
         bool in_gc_queue:1;
         bool started:1;
-        bool registered:1;
 
         sd_bus_message *create_message;
 

src/machine/machined-dbus.c

@@ -354,8 +354,6 @@ static int method_register_machine_internal(sd_bus *bus, sd_bus_message *message
                 goto fail;
         }
 
-        m->registered = true;
-
         r = machine_start(m, NULL, error);
         if (r < 0)
                 goto fail;