Fix port session premature close when local server is not connected b…

…efore timeout

cr: https://code.amazon.com/reviews/CR-70146201

agent/session/plugins/port/port_mux.go

@@ -181,11 +181,8 @@ func (p *MuxPortSession) initialize() (err error) {
 		}
 		log.Debugf("Accepted a connection %s\n", conn.LocalAddr())
 
-		config := smux.DefaultConfig()
-		// Disable smux KeepAlive or else it breaks Session Manager idle timeout.
-		config.KeepAliveDisabled = true
 		var session *smux.Session
-		if session, err = smux.Server(conn, config); err != nil {
+		if session, err = smux.Server(conn, nil); err != nil {
 			log.Errorf("Unable to setup smux server: %v", err)
 			return err
 		}

agent/session/plugins/port/port_mux_test.go

@@ -104,9 +104,7 @@ func (suite *MuxPortTestSuite) TestWritePumpFailsToRead() {
 	suite.mockDataChannel.On("IsActive").Return(true)
 
 	out, in := net.Pipe()
-	config := smux.DefaultConfig()
-	config.KeepAliveDisabled = true
-	session, _ := smux.Server(in, config)
+	session, _ := smux.Server(in, nil)
 	defer session.Close()
 	defer in.Close()
 	out.Close()
@@ -122,9 +120,7 @@ func (suite *MuxPortTestSuite) TestWritePumpWhenDatachannelIsNotActive() {
 	suite.mockDataChannel.On("IsActive").Return(false)
 
 	out, in := net.Pipe()
-	config := smux.DefaultConfig()
-	config.KeepAliveDisabled = true
-	session, _ := smux.Server(in, config)
+	session, _ := smux.Server(in, nil)
 	defer session.Close()
 	defer out.Close()
 
@@ -151,9 +147,7 @@ func (suite *MuxPortTestSuite) TestWritePump() {
 	suite.mockDataChannel.On("SendStreamDataMessage", suite.mockContext.Log(), mgsContracts.Output, payload).Return(nil)
 
 	out, in := net.Pipe()
-	config := smux.DefaultConfig()
-	config.KeepAliveDisabled = true
-	session, _ := smux.Server(in, config)
+	session, _ := smux.Server(in, nil)
 	defer session.Close()
 	defer out.Close()