Actually inline the variable

Signed-off-by: Antonio Santos <[email protected]>

pkg/tracing/lightstep/lightstep.go

@@ -29,7 +29,7 @@ type Tracer struct {
 
 // Close synchronously flushes the Lightstep tracer, then terminates it.
 func (t *Tracer) Close() error {
-	lightstepTracer.Close(t.ctx)
+	t.Tracer.Close(t.ctx)
 
 	return nil
 }