(MODULES-1570) Add java_major_version fact

Gives the major version of the Java release (ie. Java 1.7.0_71, major version is 7)

We also want to specifically return nil when java not present

spec/unit/facter/java_major_version_spec.rb

@@ -0,0 +1,27 @@
+require "spec_helper"
+
+describe Facter::Util::Fact do
+  before {
+    Facter.clear
+  }
+
+  describe "java_major_version" do
+    context 'returns major version when java_version fact present' do
+      before :each do
+        Facter.fact(:java_version).stubs(:value).returns('1.7.0_71')
+      end
+      it do
+        Facter.fact(:java_major_version).value.should == "7"
+      end
+    end
+
+    context 'returns nil when java not present' do
+      before :each do
+        Facter.fact(:java_version).stubs(:value).returns(nil)
+      end
+      it do
+        Facter.fact(:java_major_version).value.should be_nil
+      end
+    end
+  end
+end