can't mix with ipfs-cluster

#### Version information:
v0.8.0

#### Description:

I'm writing some ipfs code that brings in go-ipfs and the ipfs-cluster api, but it fails to compile.

```
go build ./...
# github.com/ipfs/go-filestore
../../../go/pkg/mod/github.com/ipfs/go-filestore@v0.0.3/fsrefstore.go:81:14: undefined: dshelp.DsKeyToCid
../../../go/pkg/mod/github.com/ipfs/go-filestore@v0.0.3/fsrefstore.go:101:21: undefined: dshelp.CidToDsKey
../../../go/pkg/mod/github.com/ipfs/go-filestore@v0.0.3/fsrefstore.go:145:21: undefined: dshelp.CidToDsKey
../../../go/pkg/mod/github.com/ipfs/go-filestore@v0.0.3/fsrefstore.go:258:9: undefined: dshelp.CidToDsKey
../../../go/pkg/mod/github.com/ipfs/go-filestore@v0.0.3/fsrefstore.go:303:16: undefined: dshelp.CidToDsKey
../../../go/pkg/mod/github.com/ipfs/go-filestore@v0.0.3/util.go:158:12: undefined: dshelp.DsKeyToCid
../../../go/pkg/mod/github.com/ipfs/go-filestore@v0.0.3/util.go:211:18: undefined: dshelp.DsKeyToCid
```

Here's the `go.mod`:
```
module paleozogt/ipfs-test

go 1.14

require (
github.com/ipfs/go-ipfs v0.8.0
github.com/ipfs/ipfs-cluster v0.13.2
)
```

Here's the `main.go`:

```
package main

import (
_ "github.com/ipfs/go-ipfs/plugin"
_ "github.com/ipfs/ipfs-cluster"
)

func main() {
}
```