Return all load balancers associated with an account

    CLI example:

    .. code-block:: bash

        salt myminion boto_elb.get_all_elbs region=us-east-1

def get_all_elbs(region=None, key=None, keyid=None, profile=None):
    '''
    Return all load balancers associated with an account

    CLI example:

    .. code-block:: bash

        salt myminion boto_elb.get_all_elbs region=us-east-1
    '''
    conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)

    try:
        return [e for e in conn.get_all_load_balancers()]
    except boto.exception.BotoServerError as error:
        log.warning(error)
        return []