Support bucket versioning (#9377)

- Implement a new xl.json 2.0.0 format to support,
  this moves the entire marshaling logic to POSIX
  layer, top layer always consumes a common FileInfo
  construct which simplifies the metadata reads.
- Implement list object versions
- Migrate to siphash from crchash for new deployments
  for object placements.

Fixes #2111

cmd/fs-v1-rwpool_test.go

@@ -46,10 +46,10 @@ func TestRWPoolLongPath(t *testing.T) {
 
 // Tests all RWPool methods.
 func TestRWPool(t *testing.T) {
-	// create posix test setup
-	_, path, err := newPosixTestSetup()
+	// create xlStorage test setup
+	_, path, err := newXLStorageTestSetup()
 	if err != nil {
-		t.Fatalf("Unable to create posix test setup, %s", err)
+		t.Fatalf("Unable to create xlStorage test setup, %s", err)
 	}
 	defer os.RemoveAll(path)