**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`
render() {
          
          return <div id="classWrongChild">{this.context.text}</div>;
        }
      }
      ClassChildWithWrongContext.contextTypes = {foo: PropTypes.string};
      const e = await render(
        <PurpleContext><ClassChildWithWrongContext /></PurpleContext>,
      );
      expect(e.textContent).toBe('');
    });
    itRenders('stateless child with wrong context', async render => {
      function StatelessChildWithWrongContext(props, context) {
        
        return <div id="statelessWrongChild">{context.text}</div>;
      }
      StatelessChildWithWrongContext.contextTypes = {
        foo: PropTypes.string,
      };
      const e = await render(
        <PurpleContext><StatelessChildWithWrongContext /></PurpleContext>,
      );
      expect(e.textContent).toBe('');
    });
    itRenders('with context passed through to a grandchild', async render => {
      function Grandchild(props, context) {