Setting the modtime of a closed file refreshed the cache item's
fingerprint before the new modtime had been applied to the remote
object. The next open then saw a fingerprint mismatch, logged "removed
cache file as stale (remote is different)" and downloaded the whole
file again, even though only the modtime had changed.
Refresh the cache fingerprint again once the remote modtime has been
set.
(cherry picked from commit 9380daed0d)
Neil Cawse
50d2430b4a