Update (which Put also uses) kept the caller's full precision modtime
in memory while the upload finalize request sends it rounded to
microseconds, so until the object was re-read the modtime did not
match what a fresh listing would report. This broke wrappers which
compare exact modtimes, such as the hasher backend's fingerprint and
the VFS cache. Round the modtime to microseconds to match what the
server stores.
Nick Craig-Wood
449397b8df