extract: let final dir appear only after success

[nfeske]

When the extract tool fails midway with the extraction of archive, the top-level directory of the incompletely extracted content is left over. From the outside it looks like the extraction is done. In particular, the download_manager of Sculpt OS wrongly interprets the situation where an archive extraction failed as a completed installation on the archive. By extracting the content to a differently named directory (e.g., suffixed with ".incomplete") and renaming the directory to its designated name as a final step, such misinterpretations could be prevented.