metrics: expose exc type for vcsserver

vcsserver/http_main.py

@@ -690,7 +690,9 b' class HTTPApplication(object):'
 
         statsd = request.registry.statsd
         if statsd:
-            statsd.incr('vcsserver_exception_total')
+            exc_type = "{}.{}".format(exception.__class__.__module__, exception.__class__.__name__)
+            statsd.incr('vcsserver_exception_total',
+                        tags=["type:{}".format(exc_type)])
         raise exception