Closes the session with the device.

def logout(cookie=None):
    '''
    Closes the session with the device.
    '''
    payload = '<aaaLogout cookie="{0}" inCookie="{0}"></aaaLogout>'.format(cookie)
    __utils__['http.query'](DETAILS['url'],
                            data=payload,
                            method='POST',
                            decode_type='plain',
                            decode=True,
                            verify_ssl=False,
                            raise_error=True,
                            headers=DETAILS['headers'])
    return