verify_checkpoint fails for conf file that imports another conf file

[hnyu]

def _create_algorithm_and_env(root_dir):
    """Create algorithm and env from config file."""
    alf.reset_configs()
    conf_file = common.get_conf_file()
    try:
        common.parse_conf_file(conf_file)

When creating the algorithm2, we use runpy to run the conf file again. However, if the conf file imports another base conf file, then runpy won't reload the module. As we've already reset all alf configs, this will make the configs in the base conf file not properly configured.

[hnyu]

@emailweixu I didn't find an easy way to force runpy reloading the modules in the config file. Any idea?

[emailweixu]

I had a fix for verify_checkpoint in my local branch a while ago.

[emailweixu]

My change #1257 does not fix your problem. It just give a better error message.