How do I turn email notifications off on the buildfarm?

edit

With this project http://jenkins.ros.org/job/ros-hydro-...

I'm getting this error which is spamming my email inbox at about 1 email a minute for the past couple of days.

[ros-hydro-pr2-navigation-teleop_sourcedeb] $ /bin/bash /tmp/hudson7223506363679838700.sh
Traceback (most recent call last):
  File "/home/rosbuild/hudson/workspace/ros-hydro-pr2-navigation-teleop_sourcedeb/monitored_vcs/scripts/generate_sourcedeb", line 119, in <module>
    rd = Rosdistro(args.rosdistro)
  File "/home/rosbuild/hudson/workspace/ros-hydro-pr2-navigation-teleop_sourcedeb/monitored_vcs/buildfarm/ros_distro.py", line 47, in __init__
    self._index = get_index(get_index_url())
  File "/usr/lib/python2.7/dist-packages/rosdistro/__init__.py", line 113, in get_index
    yaml_str = load_url(url)
  File "/usr/lib/python2.7/dist-packages/rosdistro/loader.py", line 59, in load_url
    raise URLError(str(e) + ' (%s)' % url)
urllib2.URLError: <urlopen error <urlopen error [Errno 111] Connection refused> (https://raw.github.com/ros/rosdistro/master/index.yaml)>
Build step 'Execute shell' marked build as failure
Build step 'Groovy Postbuild' marked build as failure
Description set: 
Sending e-mails to: ros-buildfarm-release@googlegroups.com dash@clearpathrobotics.com
Finished: FAILURE

It suggests that the URL can't open the index.yaml which might mean the buildfarm is purposefully shut down which I can respect and see. How do I turn email notifications off?