Add missing return statement in the webhook admissions func

As the function is currently written without a return, for an
unstructured object which is successfully unmashalled, it will fall
through to the subsequent lines and fail to decode properly.

Add return statement to successful unstructured decode.

Signed-off-by: Leah Leshchinsky <lleshchi@redhat.com>

pkg/webhook/admission/decode.go

@@ -71,6 +71,7 @@ func (d *Decoder) DecodeRaw(rawObj runtime.RawExtension, into runtime.Object) er
 			return err
 		}
 		unstructuredInto.SetUnstructuredContent(object)
+		return nil
 	}
 
 	deserializer := d.codecs.UniversalDeserializer()