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revision 1.41
date: 2022/02/20 19:24:19;  author: afresh1;  state: Exp;  lines: +3 -2;  commitid: XRrwqAIAdoPjTtj9;
Remove downloaded SHA256.sig if signature validation fails

Without the "noclobber" setting we would have overwitten with an empty
file and best not to leave a failed file around.

Noticed by florian@
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feels like it might be better to explicitly save the file for manual
checking if that happens?