Adding configtest functionality to the radio package.

https://github.com/corey-hammerton/graylog2-rpms/issues/5

Files Modified:
SOURCES/init.d-graylog2-radio
SOURCES/sysconfig-graylog2-radio
SPECS/graylog2-radio.spec

The same functionality for these files have been duplicated and
adapted from the web-interface package (see this commit's parent).