@jedp - this will set the kpi_backend_db_url field to http://localhost/wsapi/interaction_data by default.  

This was not previously defined in any configuration file, meaning all hosts will default to have this set.  This results in a kpi data falling off the planet on my local dev environment because I never run on localhost, I always assign an external IP address so that I can access the server from external devices.

Here is an extraction of my log when KPI data is sent.  You can see in the first line that I run on IP address http://10.246.29.67

```
router (75218): info: forwarding request: /wsapi/interaction_data -> http://10.246.29.67:10007/wsapi/interaction_data
browserid (75213): info: POST /wsapi/interaction_data 200 1
router (75218): info: POST /wsapi/interaction_data 200 4
browserid (75213): debug: Simulate write to KPI Backend DB - [
browserid (75213):   {
browserid (75213):     "event_stream": [
browserid (75213):       [
browserid (75213):         "screen.rp_info",
browserid (75213):         137
browserid (75213):       ],
browserid (75213):       [
browserid (75213):         "screen.authenticate",
browserid (75213):         169
browserid (75213):       ],
browserid (75213):       [
browserid (75213):         "screen.set_password",
browserid (75213):         10822
browserid (75213):       ],
browserid (75213):       [
browserid (75213):         "user.user_staged",
browserid (75213):         14283
browserid (75213):       ],
browserid (75213):       [
browserid (75213):         "screen.check_registration",
browserid (75213):         14299
browserid (75213):       ],
browserid (75213):       [
browserid (75213):         "user.user_confirmed",
browserid (75213):         27798
browserid (75213):       ],
browserid (75213):       [
browserid (75213):         "generate_assertion",
browserid (75213):         27800
browserid (75213):       ],
browserid (75213):       [
browserid (75213):         "screen.generate_assertion",
browserid (75213):         27846
browserid (75213):       ],
browserid (75213):       [
browserid (75213):         "assertion_generated",
browserid (75213):         28715
browserid (75213):       ],
browserid (75213):       [
browserid (75213):         "window.unload",
browserid (75213):         30502
browserid (75213):       ]
browserid (75213):     ],
browserid (75213):     "sample_rate": 1,
browserid (75213):     "timestamp": 1344331800000,
browserid (75213):     "lang": "en-us",
browserid (75213):     "new_account": true,
browserid (75213):     "screen_size": {
browserid (75213):       "width": 1680,
browserid (75213):       "height": 1050
browserid (75213):     },
browserid (75213):     "email_type": "secondary",
browserid (75213):     "number_emails": 1,
browserid (75213):     "sites_signed_in": 1,
browserid (75213):     "sites_visited": 1,
browserid (75213):     "orphaned": false,
browserid (75213):     "user_agent": {
browserid (75213):       "os": "Macintosh",
browserid (75213):       "browser": "Firefox",
browserid (75213):       "version": 17
browserid (75213):     }
browserid (75213):   }
browserid (75213): ]
browserid (75213): debug: sending request to KPI backendhttp://localhost/wsapi/interaction_data
```

On the very last line, you can see a request is sent to http://localhost/wsapi/interaction_data.  What happens if I do not have a KPI server running, does the attempted connection stay open or is it properly closed?

Should a default be set here, or is it better to leave it off and depend on the configuration file/environment parameter?