tests: arrange for a server in wireproto-command-capabilities.t to be killed
The stray servers were piling up after the test harness exited. On Windows,
this means the *.pyd files can't be rebuilt, which is why the build warning
count dropped to 1 recently.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}