core: no need to eat up error

This is a method call reply. We might as well propagate the error. The
worst that happens is that sd-bus logs about it.

src/core/unit.c

@@ -3227,10 +3227,8 @@ static int get_name_owner_handler(sd_bus_message *message, void *userdata, sd_bu
         }
 
         r = sd_bus_message_read(message, "s", &new_owner);
-        if (r < 0) {
-                bus_log_parse_error(r);
-                return 0;
-        }
+        if (r < 0)
+                return bus_log_parse_error(r);
 
         if (UNIT_VTABLE(u)->bus_name_owner_change)
                 UNIT_VTABLE(u)->bus_name_owner_change(u, NULL, new_owner);