Fix loader-svn [2] and loader-mercurial's [1] current ci build failure (master branch).
[1] https://jenkins.softwareheritage.org/job/DLDHG/job/tests/409/console
[2] https://jenkins.softwareheritage.org/job/DLDSVN/job/tests/397/console
Reproduced locally by removing respectively those tools and trigger tox in both repos.