Fix selection when commits have the same timestamp
Fix selection when commits have the same timestamp

When we have more than one commit with the exact same timestamp,
for example [1], we run into a situation in DLRN where the logic
for commit selection can become confused.

The reason for this is that "git log --after=<timestamp>" does not
report the commits merged after the timestamp, but also _at_ that
timestamp. This means that if we want to build a tag, we will first
build the tagged commit, but later DLRN will try to build the
other commit with the same timestamp.

To fix this, we add 1 second to the latest timestamp when running
"git log" to actually ensure that we get commits merged after the
last commit date.

[1] - https://opendev.org/openstack/oslo.log/commits/tag/4.4.0

Change-Id: Ib48dce4a1cc3a45fdbd73b806828f91927daf9aa

openstack-packages/delorean,openstack-packages/DLRN,openstack-packages/DLRN,openstack-packages/delorean