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

Report a bug.

**What is the current behavior?**

Whenever I render SVG elements that are camel cased (e.g. `<linearGradient />`) on the server side,  I get the following warning:

```
Warning: <linearGradient /> is using uppercase HTML. Always use lowercase HTML tags in React.
```

**What is the expected behavior?**

Warnings should be consistent with the client side rendering, if possible. In this case, I'd expect no warning, since using camel cased SVG element names is pretty standard.

For client side rendering, there seems to be a check for the current namespace:

https://github.com/facebook/react/blob/efcac24af26afba90e2ef525509ca40f3bd6f270/src/renderers/dom/fiber/ReactDOMFiberComponent.js#L344-L352

For server side rendering, there seems to be currently no such check in place:

https://github.com/facebook/react/blob/81706eeb7a51c1cea7fd8e66733a4f4618155ef5/src/renderers/shared/server/ReactPartialRenderer.js#L537-L544

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**

Hitting this on 16.0.0-beta.5. Was not hitting it on 15.6.1, the version I was previously on.

Thanks in advance.
warning(
      props.innerHTML == null,
      'Directly setting property `innerHTML` is not permitted. ' +
        'For more information, lookup documentation on `dangerouslySetInnerHTML`.',
    );
    warning(
      props.suppressContentEditableWarning ||
        !props.contentEditable ||
        props.children == null,
      'A component is `contentEditable` and contains `children` managed by ' +
        'React. It is now your responsibility to guarantee that none of ' +
        'those nodes are unexpectedly modified or duplicated. This is ' +
        'probably not intentional.',
    );
    warning(
      props.onFocusIn == null && props.onFocusOut == null,
      'React uses onFocus and onBlur instead of onFocusIn and onFocusOut. ' +
        'All React events are normalized to bubble, so onFocusIn and onFocusOut ' +
        'are not needed/supported by React.',
    );
  }
  invariant(
    props.style == null || typeof props.style === 'object',
    'The `style` prop expects a mapping from style properties to values, ' +
      "not a string. For example, style={{marginRight: spacing + 'em'}} when " +
      'using JSX.%s',
    getDeclarationErrorAddendum(component),
  );
}
function ensureListeningTo(inst, registrationName, transaction) {