bug fix, session stored in redis cannot be deleted

@@ -398,6 +398,7 @@ func (c *Controller) SessionRegenerateID() {
 
 // DestroySession cleans session data and session cookie.
 func (c *Controller) DestroySession() {
+	c.Ctx.Input.CruSession.Flush()
 	GlobalSessions.SessionDestroy(c.Ctx.ResponseWriter, c.Ctx.Request)
 }
 

@@ -60,6 +60,11 @@ func (rs *RedisSessionStore) SessionID() string {
 }
 
 func (rs *RedisSessionStore) SessionRelease(w http.ResponseWriter) {
+	// if rs.values is empty, return directly
+	if len(rs.values) < 1 {
+		return
+	}
+
 	c := rs.p.Get()
 	defer c.Close()