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What kind of change does this PR introduce?

Some users reported spurious "expired signature" errors. After some investigation, we found that all of them had the wrong system date set on their machine, with a date set in the past. Even if the error says that the signature is "expired", it's a signature that is not yet valid (it will be in the future).
Since we cannot trust the system clock, we recheck the signature with a future date so we may avoid displaying a difficult-to-understand error to the user.

This PR will suppress the, apparently unrelated,signature expired error in such cases.

What is the current behavior?

An index update will trigger asignature expired error if the clock is set to a past date.

What is the new behavior?

If the clock is set to a past date, an index update will no longer trigger asignature expired error.

Does this PR introduce a breaking change, and istitled accordingly?

No

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