changeset status: fix common case where a reviewer did not yet review anything When a reviewer did not yet make any review, its status for the changeset is None, causing the code to crash. The unit tests also did not cover this case.

[tox]
envlist = py{26,27}-{pytest,nose}

[testenv]
setenv =
    PYTHONHASHSEED = 0
deps =
    nose: nose
    pytest: pytest
commands =
    nose: nosetests {posargs}
    pytest: py.test {posargs}