remove old "paranoid" option, I'm pretty sure nobody uses it.

remove old "paranoid" option, I'm pretty sure nobody uses it.

refactor the code into figuring out simple updates: if we don't have
any @execs but just @tags, we can probably do something simpler wrt
temporary files and temporary filenames, which should speed up texlive
updates significantly.

(the tempfile code is not there yet, just the check for safe updates)