Set default resource dir, looks like this attribute was missing

I recently upgraded to find all my plugins giving a "Return code of 127 is out of bounds - plugin may be missing" error.

After bit of sleuthing I noticed nagios wasn't picking up resources.cfg. According to the docs, default['nagios']['resource_dir'] is supposed to be set, but from what I could tell it wasn't.

Inside the rhel/fedora block I am making an educated guess.