Delete all objects related to client
    
    @param client_id: ID of client user
    @param preserve_cache: Boolean, whether to delete the chrome profile folder or not

def delete_client(client_id, preserve_cache):
    """Delete all objects related to client
    
    @param client_id: ID of client user
    @param preserve_cache: Boolean, whether to delete the chrome profile folder or not
    """
    if client_id in drivers:
        drivers.pop(client_id).quit()
        try:
            timers[client_id].stop()
            timers[client_id] = None
            release_semaphore(client_id)
            semaphores[client_id] = None
        except:
            pass

    if not preserve_cache:
        pth = CHROME_CACHE_PATH + g.client_id
        shutil.rmtree(pth)