Update push-uniapp.js

Author: walkor

src/push-uniapp.js

@@ -195,7 +195,7 @@ function createPresenceChannel(channel_name, push)
 uni.onNetworkStatusChange(function (res) {
     if(res.isConnected) {
         for (var i in Push.instances) {
-            con = Push.instances[i].connection;
+            var con = Push.instances[i].connection;
             con.reconnectInterval = 1;
             if (con.state === 'connecting') {
                 con.connect();