fixed a issue of last commit; increase udp conv timeout to 180s

common.h

@@ -67,7 +67,7 @@ const u32_t conv_clear_interval=200;
 const u32_t timer_interval=400;
 const int conv_clear_ratio=40;
 const int conv_clear_min=5;
-const u32_t conv_timeout=20000;
+const u32_t conv_timeout=180000;
 const int max_conv_num=10000;
 
 /*

main.cpp

@@ -283,8 +283,8 @@ struct conn_manager_t  //TODO change map to unordered map
 			}
 			cnt++;
 		}
-		return 0;
 		clear_it=it;
+		return 0;
 	}
 }conn_manager;