(MAINT) declare an exclusion filter for the tests using with_env on facter 1.6

The with_env function is not available in facter 1.6 and OpenBSD is not
supported.

spec/spec_helper.rb

@@ -1 +1,6 @@
 require 'puppetlabs_spec_helper/module_spec_helper'
+
+RSpec.configure do |c|
+  # declare an exclusion filter for the tests using with_env on facter 1.6, as the function is not available on 1.6
+  c.filter_run_excluding :with_env => true if Facter.version =~ /^1\.6\./
+end

spec/unit/facter/java_version_spec.rb

@@ -7,7 +7,7 @@ describe Facter::Util::Fact do
 
   describe "java_version" do
     context 'returns java version when java present' do
-      context 'on OpenBSD' do
+      context 'on OpenBSD', :with_env => true do
         before do
           Facter.fact(:operatingsystem).stubs(:value).returns("OpenBSD")
         end
@@ -41,7 +41,7 @@ Java HotSpot(TM) 64-Bit Server VM (build 24.71-b01, mixed mode)
     end
 
     context 'returns nil when java not present' do
-      context 'on OpenBSD' do
+      context 'on OpenBSD', :with_env => true do
         before do
           Facter.fact(:operatingsystem).stubs(:value).returns("OpenBSD")
         end