Add support for OpenBSD, and also add some regression tests.

Add info about OpenBSD support to README.md and metadata.json
Add a note about OpenBSD java_version fact to README.markdown.
Fixup wording on context in one of the java patch level regression tests.
No mentioning of OpenBSD in metdata.json

Cleanup wording of context as suggested by @elyscape
update contexts as suggested by @elyscape

spec/unit/facter/java_patch_level_spec.rb

@@ -17,8 +17,8 @@ describe Facter::Util::Fact do
       end
     end
 
-    context "if java is installed" do
-      context 'returns java patch version extracted from java_version fact' do
+    context "if java is not installed" do
+      context 'returns nil' do
         before :each do
           Facter.fact(:java_version).stubs(:value).returns(nil)
         end
@@ -28,4 +28,4 @@ describe Facter::Util::Fact do
       end
     end
   end
-end
+end