error "fill(none) must be used with a function" not reported with CSV encoding

Using InfluxDB 1.8.3:

Usually, when executing a query with and without "Accept: application/csv" header, the same error is returned, ex:

query: `curl -i -X POST 'http://localhost:8086/query?db=test' --data-urlencode 'q=SELECT * FROM test FILL(foo)'` responds:
```
HTTP/1.1 400 Bad Request

{"error":"error parsing query: expected number argument in fill()"}
```

query: `curl -i -X POST 'http://localhost:8086/query?db=test' --data-urlencode 'q=SELECT * FROM test FILL(foo)' --header 'Accept: application/csv'` responds equivalently:
```
HTTP/1.1 400 Bad Request

error
error parsing query: expected number argument in fill()
```

With the following particular error though, this seems to not be the case:

query: `curl -i -X POST 'http://localhost:8086/query?db=test' --data-urlencode 'q=SELECT * FROM test FILL(none)'` responds:
```
HTTP/1.1 400 Bad Request

{"results":[{"statement_id":0,"error":"fill(none) must be used with a function"}]}
```

query: `curl -i -X POST 'http://localhost:8086/query?db=test' --data-urlencode 'q=SELECT * FROM test FILL(none)' --header 'Accept: application/csv'` however reponds:
```
HTTP/1.1 200 OK

```
i.e., simply an empty result set without an error. I presume this is a bug?

Reproduce the two curl requests against InfluxDB 1.8.3, comparing the default response with the response using the Accept: application/csv header. Trace the query endpoint's handling of the fill(none) error in each response mode. Done means both requests return HTTP 400 and report the same error.

Written by the indexing model from the issue text.