Change cleanup command to accomodate swap disk
Change cleanup command to accomodate swap disk

Hyperkit was mounting swap disks, which we can't detach with the
hdiutil util like we're using.  Its sufficient to just hdiutil detach
/dev/disk1

```
/dev/disk1	FDisk_partition_scheme
/dev/disk1s1	Linux
/dev/disk1s2	Linux_Swap
```

dlorenc/minikube,warmchang/minikube,kubernetes/minikube,warmchang/minikube,dlorenc/minikube,aaron-prindle/minikube,dlorenc/minikube,cu12/minikube,kubernetes/minikube,kubernetes/minikube,aaron-prindle/minikube,dlorenc/minikube,kubernetes/minikube,r2d4/minikube,dalehamel/minikube,cu12/minikube,kubernetes/minikube,dims/minikube,r2d4/minikube,dlorenc/minikube,warmchang/minikube,dlorenc/minikube,warmchang/minikube,kubernetes/minikube,dalehamel/minikube,warmchang/minikube,dalehamel/minikube,aaron-prindle/minikube,warmchang/minikube,warmchang/minikube,dims/minikube,dims/minikube,dlorenc/minikube,dlorenc/minikube,kubernetes/minikube,cu12/minikube,r2d4/minikube