The pull loop follows BRANCH with `git reset --hard FETCH_HEAD` whenever the branch moves.
In the cloud that is the point. On a checkout mounted from someone's machine it would wipe
their commits and uncommitted work. PULL_INTERVAL=0 now skips the loop entirely: no fetch,
no reset, one line in /tmp/pull.log saying so. Every other value behaves as before.
Checked both ways on a throwaway repo whose remote had moved on and whose working copy held an
uncommitted edit: with 0 the commit and the edit stay; with 1 (the control) the loop resets
both, as it always has.