zope.index.text.OkapiIndex reindexing is broken

[Ignas Mikalajūnas]

If we index the same document twice, once with a zero value, and then
with a normal value, it should still work:

    >>> index2 = TextIndex()
    >>> index2.index_doc(1, [])
    >>> index2.index_doc(1, ["Zorro"])

    >>> [(k, "%.4f" % v) for (k, v) in index2.apply("Zorro").items()]
    [(1, '0.4545')]

Weights are the same as if we would have indexed the document only
once:

    >>> index2 = TextIndex()
    >>> index2.index_doc(1, ["Zorro"])

    >>> [(k, "%.4f" % v) for (k, v) in index2.apply("Zorro").items()]
    [(1, '0.4545')]

Test case (textindex.txt)

fixed _reindex_doc for OkapiIndex:

    def _reindex_doc(self, docid, text):
        old_docw = self._docweight[docid]
        count = BaseIndex._reindex_doc(self, docid, text)
        if count > -1:
            self._totaldoclen -= old_docw
        return count

[Ignas Mikalajūnas (ignas)]

Fix applied (except for the part with weight checking), weights are calculated separately. And released as an egg.