[FAB-3410] Improve unit test for txmgmt/version

Increase the test coverage from 77% to 100%.

Change-Id: I137c8741681a9a21558900bc1ec9b1cd8ac45af3
Signed-off-by: senthil <cendhu@gmail.com>

Author: cendhu

core/ledger/kvledger/txmgmt/version/version_test.go

@@ -35,6 +35,10 @@ func TestVersionComparison(t *testing.T) {
 	testutil.AssertEquals(t, NewHeight(10, 100).Compare(NewHeight(10, 90)), 1)
 	testutil.AssertEquals(t, NewHeight(10, 100).Compare(NewHeight(11, 1)), -1)
 	testutil.AssertEquals(t, NewHeight(10, 100).Compare(NewHeight(10, 100)), 0)
+
+	testutil.AssertEquals(t, AreSame(NewHeight(10, 100), NewHeight(10, 100)), true)
+	testutil.AssertEquals(t, AreSame(nil, nil), true)
+	testutil.AssertEquals(t, AreSame(NewHeight(10, 100), nil), false)
 }
 
 func TestVersionExtraBytes(t *testing.T) {