Fix zpages type data for SFx receiver (#153)

* Fix zpages type data for SFx receiver

The issue was the use of incorrect obsreport function to start the operation. Since the other functions were correct this only affected the pages. Also upon inspection noticed a missing cal to span.End if the receive operation ended before ingress data could be decoded.

* Testbed: increase memory usage for Carbon receiver test

This failed on CircleCI saying that it reached 61MiB, the code isn't affected by PR.

receiver/signalfxreceiver/receiver.go

@@ -155,7 +155,7 @@ func (r *sfxReceiver) Shutdown() error {
 
 func (r *sfxReceiver) handleReq(resp http.ResponseWriter, req *http.Request) {
 	ctx := obsreport.ReceiverContext(req.Context(), r.config.Name(), "http", r.config.Name())
-	ctx = obsreport.StartTraceDataReceiveOp(ctx, r.config.Name(), "http")
+	ctx = obsreport.StartMetricsReceiveOp(ctx, r.config.Name(), "http")
 
 	if req.Method != http.MethodPost {
 		r.failRequest(ctx, resp, http.StatusBadRequest, invalidMethodRespBody, nil)
@@ -255,6 +255,7 @@ func (r *sfxReceiver) failRequest(
 		traceStatus.Message = err.Error()
 	}
 	reqSpan.SetStatus(traceStatus)
+	reqSpan.End()
 
 	r.logger.Debug(
 		"SignalFx receiver request failed",

testbed/tests/metric_test.go

@@ -43,7 +43,7 @@ func TestMetric10kDPS(t *testing.T) {
 			NewCarbonDataReceiver(testbed.GetAvailablePort(t)),
 			testbed.ResourceSpec{
 				ExpectedMaxCPU: 115,
-				ExpectedMaxRAM: 60,
+				ExpectedMaxRAM: 65,
 			},
 		},
 		{