Write-Result writes <result>.<pid>.tmp and then Moves/Replaces it over the
result. When both fail (result path locked, a directory, ACLs) the catch only
logged, leaving one tmp file per hand-off beside the result. The tmp is now
removed in a finally (it is gone already after a successful publish), the
same as posix.sh's write_result.
Test (Windows live cell): with the result path occupied by a directory the
hand-off still exits 0 and leaves no .hermes-update-result.json.*.tmp.
review S4
6b97fee9c2