**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('value')).toBe(null);
          expect(e.getAttribute('defaultValue')).toBe(null);
          expect(e.value).toBe('foo');
        },
      );
    });
    describe('selects', function() {
      var options;
      beforeEach(function() {
        options = [
          <option key={1} value="foo" id="foo">Foo</option>,
          <option key={2} value="bar" id="bar">Bar</option>,
          <option key={3} value="baz" id="baz">Baz</option>,
        ];
      });
      
      
      
      const expectSelectValue = (element, selected) => {
        if (!Array.isArray(selected)) {
          selected = [selected];
        }
        
        
        expect(element.getAttribute('value')).toBe(null);
        expect(element.getAttribute('defaultValue')).toBe(null);
        ['foo', 'bar', 'baz'].forEach(value => {
          const expectedValue = selected.indexOf(value) !== -1;
          var option = element.querySelector(`#${value}`);