fixed flaky code that triggered failure to publish

publishing to openhome.org occurred too early (and too often);
ohNet-Nightly #956 failed on Windows-x86 (only), since debug build
had not yet been renamed when release build was already uploaded;
still unversioned debug build found eponmyous file at destination
and was so large that ssh timed out underneath rsync;
now also defensively clear Build/Bundles before populating it afresh