pid1: properly propagate errors from device_setup_unit()

We want to propagate errors here, since we want to make dependent on the
success of creating the main device unit the creation of the auxiliary
device units. Thus if we suppress errors here we might end up in exotic
corner cases in a situation were we create the auxiliary ("following")
device units without the primary one.

src/core/device.c

@@ -493,10 +493,8 @@ static int device_setup_unit(Manager *m, sd_device *dev, const char *path, bool
 
         if (dev) {
                 r = sd_device_get_syspath(dev, &sysfs);
-                if (r < 0) {
-                        log_device_debug_errno(dev, r, "Couldn't get syspath from device, ignoring: %m");
-                        return 0;
-                }
+                if (r < 0)
+                        return log_device_debug_errno(dev, r, "Couldn't get syspath from device, ignoring: %m");
         }
 
         r = unit_name_from_path(path, ".device", &e);