**Do you want to request a *feature* or report a *bug*?**
Bug

**What is the current behavior?**
I've started recieving this warning about my SVGs which is using [feGaussianBlur](https://developer.mozilla.org/en-US/docs/Web/SVG/Element/feGaussianBlur): 
`Warning: Expected server HTML to contain a matching <feGaussianBlur> in <filter>.`

**What is the expected behavior?**
Should be no warnings because there are no difference.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
Such behavior started right after updating to `React 16.0.0-rc.3` and never happened with `React 15.6.1`
parentNamespace,
    );
    precacheFiberNode(internalInstanceHandle, domElement);
    updateFiberProps(domElement, props);
    return domElement;
  },
  appendInitialChild(
    parentInstance: Instance,
    child: Instance | TextInstance,
  ): void {
    parentInstance.appendChild(child);
  },
  finalizeInitialChildren(
    domElement: Instance,
    type: string,
    props: Props,
    rootContainerInstance: Container,
  ): boolean {
    setInitialProperties(domElement, type, props, rootContainerInstance);
    return shouldAutoFocusHostComponent(type, props);
  },
  prepareUpdate(
    domElement: Instance,
    type: string,
    oldProps: Props,
    newProps: Props,
    rootContainerInstance: Container,
    hostContext: HostContext,
  ): null | Array<mixed> {
    if (__DEV__) {