Http::request - get callers for ApiService::foreignCall and report to Logstash

@wladekb / @jcellary 

``ApiService:: foreignCall`` is being reported to Logstash. Adding it to the "blacklist" of ``wfGetCallerClassMethod`` function will report the "real" caller and make stats more meaningful.

HTTP requests stats from last hour:

```json
 {
  "count": 5779, 
  "min": 10.0, 
  "sum_of_squares": 97660073.0, 
  "max": 858.0, 
  "sum": 608423.0, 
  "std_deviation": 76.25543745823305, 
  "key": "apiservice:foreigncall", 
  "variance": 5814.8917419464915, 
  "avg": 105.28170963834573
 }
```