use static timestamps for api samples
use static timestamps for api samples

Building Aodh cannot be done in a reproducible manner,
due to the use of timestamps.

If you don't know about reproducible builds, please read on:
https://wiki.debian.org/ReproducibleBuilds
https://wiki.debian.org/ReproducibleBuilds/About

This patch is a forward of the Debian bug patch sent here:
https://bugs.debian.org/820179

Change-Id: I41550ee36a1d2539fd1d3bd7fc046bff240e9f67
Closes-Bug: #1572432

openstack/aodh,openstack/aodh