mock tests: less verbose log output checking

parseMockLogs is called potentially multiple times while waiting for
output. Dumping all CSI calls each time is quite verbose and
repetitive. To verify what the driver has done already, the normal
capturing of the container log can be used instead:

csi-mockplugin-0/mock@127.0.0.1: gRPCCall: {"Method":"/csi.v1.Node/NodePublishVolume","Request"...

test/e2e/storage/csi_mock_volume.go

@@ -944,7 +944,6 @@ func parseMockLogs(cs clientset.Interface, namespace, driverPodName, driverConta
 	if err != nil {
 		return nil, fmt.Errorf("could not load CSI driver logs: %s", err)
 	}
-	framework.Logf("CSI driver logs:\n%s", log)
 
 	logLines := strings.Split(log, "\n")
 	var calls []mockCSICall