repoview: fix the filter created by `extrafilter`
The `name` variable was updated in each interaction of the loop, making all new
filters inheriting from the same base (the last one iterated), leading to
terrible terrible misbehavior.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}