Cashew: Fix AggregatorTest.TrimOld for roundoff

The AggregatorTest.TrimOld can fail randomly due to round-off error
in converting backwards and forwards between day and date.  The
underlying function under test has no need to be hour-accurate, so
remove this test and instead test forwards and backwards by a day
and two days.

Partially reverts f04c4bd726b6acc527b1e4a224f03eb33bbad47a

BUG=chromium-os:27657
TEST=Manual, rerun unit tests.

Change-Id: I78bc2f3b3aae6debcceb5e669499633c34d91565
Reviewed-on: https://gerrit.chromium.org/gerrit/17989
Reviewed-by: Chris Masone <cmasone@chromium.org>
Reviewed-by: Jason Glasgow <jglasgow@chromium.org>
Commit-Ready: Paul Stewart <pstew@chromium.org>
Tested-by: Paul Stewart <pstew@chromium.org>
1 file changed