Scrapyd failing to start after an unclean shutdown

After an unclean shutdown Scrapyd fails to start during server boot up, this leaves the service offline until it is manually started.
We have seen this issue on Registry multiple times.

One solution to help start Scrapyd on boot would be for systemd to retry the service, for example:

```
[Unit]
StartLimitInterval=200
StartLimitBurst=5

[Service]
Restart=always
RestartSec=30
```