"asr: Couldn't personalize volume" on Mojave

I kept running into this issue with `Install macOS Mojave.app` when the `prepare-iso.sh` script would get to the `asr restore` command:

```
Validating target...done
Validating source...done
Retrieving scan information...done
Validating sizes...done
Restoring ....10....20....30....40....50....60....70....80....90....100
Restored target device is /dev/disk4s2.
Remounting target volume...done
Personalization succeeded
asr: Couldn't personalize volume /Volumes/macOS Base System
```

Oddly enough, though, it appears the "Personalization succeeded," but this emits a non-zero status, so the script dies right here.

I decided to see if I could manually run the commands that followed to see what would happen, and sure enough, everything succeeds, but there was one other thing I needed to change.

I needed to replace:

/Volumes/OS\ X\ Base\ System

with:

/Volumes/macOS\ Base\ System

For Mojave, it appears that, when the `asr restore` command mounts the volume for the base system, it uses the name "macOS Base System" instead of the older "OS X Base System."