go/mirko: fix trace logging

Change-Id: I95b8ce32ad529ffe0b43282f5761495df78b2b10
diff --git a/go/mirko/trace.go b/go/mirko/trace.go
index 33b4352..7ec4e37 100644
--- a/go/mirko/trace.go
+++ b/go/mirko/trace.go
@@ -12,7 +12,7 @@
 	tr, ok := trace.FromContext(ctx)
 	if !ok {
 		fmtd := fmt.Sprintf(f, args...)
-		glog.Info("[no trace] %v", fmtd)
+		glog.Infof("[no trace] %v", fmtd)
 		return
 	}
 	tr.LazyPrintf(f, args...)