fix the thread stop bug, must wait when not joinable.

@@ -539,8 +539,6 @@ void SrsServer::destroy()
     }
     
     srs_freep(signal_manager);
-    
-    srs_freep(handler);
 }
 
 void SrsServer::dispose()

@@ -293,10 +293,14 @@ private:
     virtual void dispose();
 // server startup workflow, @see run_master()
 public:
+    /**
+     * initialize server with callback handler.
+     * @remark user must free the cycle handler.
+     */
     virtual int initialize(ISrsServerCycle* cycle_handler);
+    virtual int initialize_st();
     virtual int initialize_signal();
     virtual int acquire_pid_file();
-    virtual int initialize_st();
     virtual int listen();
     virtual int register_signal();
     virtual int http_handle();

@@ -129,11 +129,13 @@ namespace internal {
                 if (ret) {
                     srs_warn("core: ignore join thread failed.");
                 }
+            }
             
             // wait the thread actually terminated.
             // sometimes the thread join return -1, for example,
             // when thread use st_recvfrom, the thread join return -1.
             // so here, we use a variable to ensure the thread stopped.
+            // @remark even the thread not joinable, we must ensure the thread stopped when stop.
             while (!really_terminated) {
                 st_usleep(10 * 1000);
                 
@@ -142,7 +144,6 @@ namespace internal {
                 }
                 srs_warn("core: wait thread to actually terminated");
             }
-            }
             
             tid = NULL;
         }