**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`
expect(e.getAttribute('htmlFor')).toBe('test');
      });
      itRenders('for attribute on custom elements', async render => {
        const e = await render(<div is="custom-element" for="test" />);
        expect(e.getAttribute('for')).toBe('test');
      });
    });
    describe('numeric properties', function() {
      itRenders(
        'positive numeric property with positive value',
        async render => {
          const e = await render(<input size={2} />);
          expect(e.getAttribute('size')).toBe('2');
        },
      );
      itRenders(
        'no positive numeric property with zero value',
        async render => {
          const e = await render(<input size={0} />);
          expect(e.hasAttribute('size')).toBe(false);
        },
      );
      itRenders('numeric property with zero value', async render => {
        const e = await render(<ol start={0} />);
        expect(e.getAttribute('start')).toBe('0');
      });
    });
    describe('props with special meaning in React', function() {
      itRenders('no ref attribute', async render => {
        class RefComponent extends React.Component {