List key_policies for the specified key.

    CLI example::

        salt myminion boto_kms.list_key_policies 'alias/mykey'

def list_key_policies(key_id, limit=None, marker=None, region=None, key=None,
                      keyid=None, profile=None):
    '''
    List key_policies for the specified key.

    CLI example::

        salt myminion boto_kms.list_key_policies 'alias/mykey'
    '''
    conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)

    if key_id.startswith('alias/'):
        key_id = _get_key_id(key_id)
    r = {}
    try:
        key_policies = conn.list_key_policies(
            key_id,
            limit=limit,
            marker=marker
        )
        # TODO: handle limit, marker and truncation automatically.
        r['key_policies'] = key_policies['PolicyNames']
    except boto.exception.BotoServerError as e:
        r['error'] = __utils__['boto.get_error'](e)
    return r