autopilot test should use Mouse as pointer for desktop

[Chris Gagnon]

This is outside of the autopilot 1.4 port,

we need to update the tests/autopilot/ubuntu_keyboard/tests/test_keyboard.py

from

super(UbuntuKeyboardTests, self).setUp()
self.pointer = Pointer(Touch.create())

to

super(UbuntuKeyboardTests, self).setUp()
if model() == "Desktop":
    self.pointer = Pointer(Mouse.create())
else:
    self.pointer = Pointer(Touch.create())