Change all references to nagios-nrpe-server in the init to use service_name attribute

This fixes a long standing bug where NRPE couldn't be stopped on RHEL
systems because the killproc uses the nagios-nrpe-server name
Merge pull request #100 from tas50/COOK-2134

COOK-2134: Correctly use nrpe vs. nagios-nrpe-server when necessary