tls: do not confuse TLSSocket and Socket

Don't use "socket" to describe two different objects in the same
function.

PR-URL: nodejs#25153
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>

lib/_tls_wrap.js

@@ -1224,7 +1224,7 @@ exports.connect = function connect(...args) {
 
   const context = options.secureContext || tls.createSecureContext(options);
 
-  var socket = new TLSSocket(options.socket, {
+  var tlssock = new TLSSocket(options.socket, {
     pipe: !!options.path,
     secureContext: context,
     isServer: false,
@@ -1235,12 +1235,14 @@ exports.connect = function connect(...args) {
     requestOCSP: options.requestOCSP
   });
 
-  socket[kConnectOptions] = options;
+  tlssock[kConnectOptions] = options;
 
   if (cb)
-    socket.once('secureConnect', cb);
+    tlssock.once('secureConnect', cb);
 
   if (!options.socket) {
+    // If user provided the socket, its their responsibility to manage its
+    // connectivity. If we created one internally, we connect it.
     const connectOpt = {
       path: options.path,
       port: options.port,
@@ -1249,22 +1251,22 @@ exports.connect = function connect(...args) {
       localAddress: options.localAddress,
       lookup: options.lookup
     };
-    socket.connect(connectOpt, socket._start);
+    tlssock.connect(connectOpt, tlssock._start);
   }
 
-  socket._releaseControl();
+  tlssock._releaseControl();
 
   if (options.session)
-    socket.setSession(options.session);
+    tlssock.setSession(options.session);
 
   if (options.servername)
-    socket.setServername(options.servername);
+    tlssock.setServername(options.servername);
 
   if (options.socket)
-    socket._start();
+    tlssock._start();
 
-  socket.on('secure', onConnectSecure);
-  socket.once('end', onConnectEnd);
+  tlssock.on('secure', onConnectSecure);
+  tlssock.once('end', onConnectEnd);
 
-  return socket;
+  return tlssock;
 };