(#19293) Enhance the release fact for OpenBSD

Currently facter only outputs the main release version number without
the actual substring information.
e.g. 5.3 versus 5.3-beta
(maint) Whitespace fix for kernelrelease_spec.rb
(#19293) Unit tests for openbsd kernelrelease fact
Merge branch 'pull-440'

This closes GH-440