hgweb: ensure isdirectory is None for repositories, replacing any True value Until now, repositories did not provide any value for isdirectory in rows produced for the index output, and thus isdirectory was generally evaluated as None for each index entry representing a repository. However, directories (visible when viewed with the descend and collapse settings enabled) did provide a value of True and this value appeared to persist in subsequent rows processed by the templater, causing isdirectory tests in templates to produce incorrect results for index entries appearing after directories. This patch asserts the None value for repositories, thus erasing any such persistent True values.