systemd-analyze verify doesn't return non-zero in all circumstances we'd want it to.

For example:

```
❯ systemd-analyze verify ./test.service
/home/justin/test.service:4: Unknown key 'WantedBy' in section [Unit], ignoring.
/home/justin/test.service:11: Unknown section 'test'. Ignoring.
/home/justin/user.slice:2: Unknown key 'WhatIsThis' in section [Unit], ignoring.
/home/justin/user.slice:6: Unknown section 'Service'. Ignoring.
❯ echo $status
0
```