Adding ___ as a species results in ____ being addeed to the lblannot table

[Erotemic]

The idea was that ____ should never be stored as a value in the lblannot table because it represents an unknown value.

Test code for this example is provided in the example section of get_species_lblannot_rowid and copied here for convenience

        Example:
            >>> from ibeis.control.IBEISControl import *  # NOQA
            >>> import ibeis
            >>> import utool
            >>> ibs = ibeis.opendb('testdb1')
            >>> species_list = [u'jaguar', u'zebra_plains',
            ...                 u'zebra_plains','____', u'zebra_grevys',
            ...                 '____', u'zebra_grevys',
            ...                 u'bear_polar', u'bear_polar', 'TYPO', '____']
            >>> ensure = False
            >>> species_rowid_list = ibs.get_species_lblannot_rowid(species_list, ensure)
            >>> print(utool.list_str(list(zip(species_list, species_rowid_list))))
            >>> ensure = True
            >>> species_rowid_list = ibs.get_species_lblannot_rowid(species_list, ensure)
            >>> print(utool.list_str(list(zip(species_list, species_rowid_list))))
            >>> ibs.print_lblannot_table()

[Erotemic]

stale