HTTP notifier does not work as expected

I have the following configuration:

```
[notifier.kafkastatus]
class-name="http"
interval=60
threshold=1
timeout=60
keepalive=60
extras={ env="dev" }
send-close=true
url-open="http://my-host:9777/kafkastatus/open"
method-open="POST"
template-open="/etc/burrow/post.tmpl"
url-close="http://my-host:9777/kafkastatus/close"
method-close="POST"
template-close="/etc/burrow/post.tmpl"

```
The post.tmpl looks like this:
```

{
"cluster":"{{.Result.Cluster}}",
"group":"{{.Result.Group}}",
"status":"{{.Result.Status.String}}",
"complete":"{{.Result.Complete}}",
"events":{{.Result.Partitions | jsonencoder}}
}

```

No HTTP notifications are sent at all. I have tried different thresholds with the same result.

No source file or test is named. Start by reproducing the HTTP notifier with the supplied configuration and template, then trace how the notifier loads its URLs, methods, templates, and threshold settings. Done means the configured open and close HTTP notifications are sent as expected, with the template data rendered correctly.

Written by the indexing model from the issue text.