tls: fix setting NPN protocols

The NPN protocols was set on `require('tls')` or `global` object instead
of being a local property. This fact lead to strange persistence of NPN
protocols, and sometimes incorrect protocol selection (when no NPN
protocols were passed in client options).

fix #6168

lib/tls.js

@@ -1321,12 +1321,13 @@ exports.connect = function(/* [port, host], options, cb */) {
 
   var sslcontext = crypto.createCredentials(options);
 
-  convertNPNProtocols(options.NPNProtocols, this);
+  var NPN = {};
+  convertNPNProtocols(options.NPNProtocols, NPN);
   var hostname = options.servername || options.host || 'localhost',
       pair = new SecurePair(sslcontext, false, true,
                             options.rejectUnauthorized === true ? true : false,
                             {
-                              NPNProtocols: this.NPNProtocols,
+                              NPNProtocols: NPN.NPNProtocols,
                               servername: hostname,
                               cleartext: options.cleartext,
                               encrypted: options.encrypted

test/simple/test-tls-npn-server-client.js

@@ -61,6 +61,12 @@ var clientsOptions = [{
   crl: serverOptions.crl,
   NPNProtocols: ['c', 'b', 'e'],
   rejectUnauthorized: false
+},{
+  port: serverPort,
+  key: serverOptions.key,
+  cert: serverOptions.cert,
+  crl: serverOptions.crl,
+  rejectUnauthorized: false
 },{
   port: serverPort,
   key: serverOptions.key,
@@ -91,7 +97,9 @@ function startTest() {
   connectClient(clientsOptions[0], function() {
     connectClient(clientsOptions[1], function() {
       connectClient(clientsOptions[2], function() {
-        server.close();
+        connectClient(clientsOptions[3], function() {
+          server.close();
+        });
       });
     });
   });
@@ -100,6 +108,8 @@ function startTest() {
 process.on('exit', function() {
   assert.equal(serverResults[0], clientsResults[0]);
   assert.equal(serverResults[1], clientsResults[1]);
-  assert.equal(serverResults[2], 'first-priority-unsupported');
+  assert.equal(serverResults[2], 'http/1.1');
   assert.equal(clientsResults[2], false);
+  assert.equal(serverResults[3], 'first-priority-unsupported');
+  assert.equal(clientsResults[3], false);
 });