Only run New Relic notifications on primary prod

* Now this task only gets run on 1 server (the primary), it will also
* only run on the production stage (but this is configurable via setting
:new_relic_stages
Whitespace commit

* See revision 95f2578772633583511c87011c2e5edf2899a044 for the last
real code change
Merge pull request #18 from amaabca/new-relic-notification

New relic notification only for primary production servers