Always capture timestamps, even if it is the same. This is because we are dependent
on it later on in the repo update process. Specifically, when updating from a HTTP
server that doesn't send out etags with its responses, it will trigger a full blown
repo update every time, even if all the values in the index are the same (name,
description, etc). This is as distinct from better behaving servers that send etags,
in which case we will only do a partial update (i.e. persist the "last updated time").
In such a case, the remainder of the update process will proceed, and ask for this
timestamp.
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