The NewRelic module relies on yfronto/newrelic, which no longer exists.
yfronto deleted that directory quite awhile ago, and since then it has
been vendored.
But vendoring a missing repository creates problems when trying to
update the vendored code.
This PR brings the yfronto/newrelic code into the mainline.
Signed-off-by: Chris Cummer <chriscummer@me.com>
