Apply prefer-const lint rule

lib/api-functions.js

@@ -139,8 +139,7 @@ function httpConReq(
           .get(options, res => {
             if (res.statusCode === 0) {
               // Workaround for some devices unexpectedly closing the connection
-              let req2;
-              req2 = http
+              const req2 = http
                 .get(options, res2 => {
                   callback(statusToError(res2.statusCode));
                   res2.resume();
@@ -155,7 +154,6 @@ function httpConReq(
                     req2.abort();
                   });
                 });
-              req2();
             } else {
               callback(statusToError(res.statusCode));
             }
@@ -223,7 +221,8 @@ function connectionRequest(deviceId, callback) {
     // TR-098 data model
     else managementServer = device.InternetGatewayDevice.ManagementServer;
 
-    connectionRequestUrl = managementServer.ConnectionRequestURL._value;
+    if (managementServer.ConnectionRequestURL)
+      connectionRequestUrl = managementServer.ConnectionRequestURL._value;
     if (managementServer.UDPConnectionRequestAddress) {
       udpConnectionRequestAddress =
         managementServer.UDPConnectionRequestAddress._value;
@@ -320,7 +319,7 @@ function insertTasks(tasks, callback) {
     return void callback(null, tasks || []);
 
   let counter = tasks.length;
-  for (let task of tasks) {
+  for (const task of tasks) {
     sanitizeTask(task, t => {
       if (t.uniqueKey) {
         db.tasksCollection.remove(