fix mispell (#54)

* fix mispell

* update golint path in travis

* Golint requires Go 1.9 or later

* install golint only if go >=1.9

* exclude go 1.7 and go 1.8 for golint

* add build on go 1.10.x

device.go

@@ -28,7 +28,7 @@ type DeviceDesc struct {
 	Bus     int   // The bus on which the device was detected
 	Address int   // The address of the device on the bus
 	Speed   Speed // The negotiated operating speed for the device
-	Port	int   // The usb port on which the device was detected
+	Port    int   // The usb port on which the device was detected
 
 	// Version information
 	Spec   BCD // USB Specification Release Number