kallithea: changeset status: fix common case where a reviewer di...

[Our Own Kallithea]

changeset: 99f090563f5f
URL:     https://kallithea-scm.org/repos/kallithea/changeset/99f090563f5f
branch:  
user:    Thomas De Schampheleire <thomas.de.schampheleire at gmail.com>
date:    Mon Apr 20 17:02:42 2015 +0200
description:
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.