Do not track anonymous sessions

And DRY the controller a bit.

services/web/app/coffee/Features/Analytics/AnalyticsController.coffee

@@ -4,25 +4,25 @@ AuthenticationController = require("../Authentication/AuthenticationController")
 
 module.exports = AnalyticsController =
 	updateEditingSession: (req, res, next) ->
-		userId    = AuthenticationController.getLoggedInUserId(req) or req.sessionID
+		userId    = AuthenticationController.getLoggedInUserId(req)
 		projectId = req.params.projectId
 
-		AnalyticsManager.updateEditingSession userId, projectId, {}, (error) ->
-			if error instanceof Errors.ServiceNotConfiguredError
-				# ignore, no-op
-				return res.send(204)
-			else if error?
-				return next(error)
-			else
-				return res.send 204
+		if userId?
+			AnalyticsManager.updateEditingSession userId, projectId, {}, (error) ->
+				respondWith(error, res, next)
+		else
+			res.send 204
 
 	recordEvent: (req, res, next) ->
 		user_id = AuthenticationController.getLoggedInUserId(req) or req.sessionID
 		AnalyticsManager.recordEvent user_id, req.params.event, req.body, (error) ->
-			if error instanceof Errors.ServiceNotConfiguredError
-				# ignore, no-op
-				return res.send(204)
-			else if error?
-				return next(error)
-			else
-				return res.send 204
+			respondWith(error, res, next)
+
+respondWith = (error, res, next) ->
+	if error instanceof Errors.ServiceNotConfiguredError
+		# ignore, no-op
+		res.send(204)
+	else if error?
+		next(error)
+	else
+		res.send 204