Revised newrelic logging approach to go to file instead of stderr.

Updated the bin/heroku-php-* and bin/heroku-hhvm-* to include the
newrelic logs files (there are 2 of them) in the stuff redirected to
$wait_pipe.  This approach should allow ```heroku logs -t``` to include
content from both the newrelic daemon and agent logs.
Merge branch 'newrelic_ini_fix' of github.com:aheusser/heroku-buildpack-php into newrelic_ini_fix