Sense breaks on HEAD verb

```
# add a document
PUT /website/blog/123
{
"title": "hello there"
}

# get to make sure it's in... it is!
GET /website/blog/123

# break Sense :)
HEAD /website/blog/123
```

Spits out

```
Error: Uncaught TypeError: Cannot read property 'promise' of undefined (http://localhost:5601/bundles/sense.bundle.js:23015)
at window.onerror (http://localhost:5601/bundles/commons.bundle.js:57730:25)
```