Add description for the irkerhook-git helper script. The debian packages add a irkerhook-git helper script, which simplifies the most common use case for irkerhook with git. This patch mentions the helper script in the irkerhook manpage.
env-service Properly import environment from /etc/defaults (Closes: #832322)
This fixes a regression in the systemd unit, which doesn't support the equivalent /etc/default/irker configuration supported by the sysvinit startup scripts.
