Synopsis:

        sys_frename(filename,new_filename)

Arguments:

        filename               -   The name of the file to rename

        new_filename       -   The new name of the file

Description: This function attempts to rename the file specified by filename to the new_filename specified.      The directory path of the  new_filename can be different to the original filename in which case the file will moved to the new directory path

Return Value:

This function will return 0 on success or a negative error code.