mercurial/templates/json/graph.tmpl

run-tests: rename `lcmd` variable to `line_cmd`

This is clearer and more in line with some other variable names.

(This is a gratuitous cleanup that I made while investigating a bug).

\{
  "node": {node|json},
  "changeset_count": {changesets|json},
  "changesets": [{join(nodes%graphentry, ", ")}]
}