Params override is not honoured 

Use the folowing `nextflow.config` 

```
profiles {
    local {
        params.genome = '/local/genome'
    }

    cloud {
        params.genome = 'gs://genome'
    }
}
```

then run 

```
nextflow config -profile cloud,local
```


If prints 

```
params {
   genome = 'gs://genome'
}
```

Instead of 


```
params {
   genome = '/local/genome'
}
```