🐞 `SIGSEGV` when mistakenly trying to access etcd
🐞 `SIGSEGV` when mistakenly trying to access etcd

When running on a BOSH-deployed Bionic stemmcell, we panic when there's
no `etcd`

Curiously, the failure on macOS is entirely different
(`context.deadlineExceededError`)

```
[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x93d10e]

goroutine 34 [running]:
go.etcd.io/etcd/client/v3.(*Client).Put(0x0, {0xb4cb68, 0xc0002730e0}, {0xc0000eceac, 0xf9cf40}, {0xc0000ecea4, 0x0}, {0x0, 0x0, 0x0})
        <autogenerated>:1 +0x4e
xip/xip.Xip.putKv({{0xc0000ece48, 0x4, 0x4}, {0xb4ccb8, 0x0}, 0xc0000890e0}, {0xc0000eceac, 0x6}, {0xc0000ecea4,
 0x7})
        /var/vcap/data/compile/sslip.io-dns-server/src/xip/xip.go:880 +0x136
```

cunnie/sslip.io,cunnie/sslip.io,cunnie/sslip.io,cunnie/sslip.io