Autopilot failure: test_recording_stop

There seems to be a timing issue in this test. The most apparent being the fact that we don't verify in the test if video mode became active before trying to record video.

....
# Click the record button to toggle photo/video mode then start recording
        self.pointing_device.move_to_object(record_control)
        self.pointing_device.click()
        self.pointing_device.move_to_object(exposure_button)
        self.pointing_device.click()

Please change the test to ensure video mode switch succeeded before trying to record video. The relevant failure can be seen here: http://ci.ubuntu.com/smokeng/vivid/touch/mako/171:20150414:20150210/12613/camera_app/2125693/