Remove unused locks that do not currently (with regard to repositories
    used) lock any package.

    root
        Operate on a different root directory.

    CLI Example:

    .. code-block:: bash

        salt '*' pkg.clean_locks

def clean_locks(root=None):
    '''
    Remove unused locks that do not currently (with regard to repositories
    used) lock any package.

    root
        Operate on a different root directory.

    CLI Example:

    .. code-block:: bash

        salt '*' pkg.clean_locks
    '''
    LCK = "removed"
    out = {LCK: 0}
    locks = os.path.join(root, os.path.relpath(LOCKS, os.path.sep)) if root else LOCKS
    if not os.path.exists(locks):
        return out

    for node in __zypper__(root=root).xml.call('cl').getElementsByTagName("message"):
        text = node.childNodes[0].nodeValue.lower()
        if text.startswith(LCK):
            out[LCK] = text.split(" ")[1]
            break

    return out