In the unlikely even that the haproxy restarts after being
configured, if the amphora is using systemd, the haproxy may
fail to start. This is due to a missing "peer ID" command line option.
This patch fixes the systemd unit to have the required "peer ID".
Change-Id: I79cfc9a2e53b249337a189bdb08d13b24807021e
Story: 2002638
Task: 22294