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

**What is the current behavior?**
If there is a client/server mismatch for text inside of an a or button element, it causes it to be automatically focused on page load.

**If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via https://jsfiddle.net or similar (template for React 16: https://jsfiddle.net/Luktwrdm/, template for React 15: https://jsfiddle.net/hmbg7e9w/).**
```
let text;
let URL = '/randomURL';
if (typeof window !== 'undefined') {
  text = 'CLIENT TEXT';
} else {
  text = 'TEXT';
}

return (
  <a href={URL}>
    {text}
  </a>
);
```

if the focus is not on the window (i.e. if a dom element is selected in the chrome inspector or react inspector widnow), then it doesn't add the focus.

**What is the expected behavior?**
The expected behavior is that it would either show CLIENT TEXT or TEXT (depending on how React16 resolves the diff), but for it not to be automatically highlighted 

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
React16 / macosx / chrome + ff + safari
props: Props,
    rootContainerInstance: Container,
    hostContext: HostContext,
    internalInstanceHandle: Object,
  ): Instance {
    let parentNamespace: string;
    if (__DEV__) {
      
      const hostContextDev = ((hostContext: any): HostContextDev);
      validateDOMNesting(type, null, hostContextDev.ancestorInfo);
      if (
        typeof props.children === 'string' ||
        typeof props.children === 'number'
      ) {
        const string = '' + props.children;
        const ownAncestorInfo = updatedAncestorInfo(
          hostContextDev.ancestorInfo,
          type,
          null,
        );
        validateDOMNesting(null, string, ownAncestorInfo);
      }
      parentNamespace = hostContextDev.namespace;
    } else {
      parentNamespace = ((hostContext: any): HostContextProd);
    }
    const domElement: Instance = createElement(
      type,
      props,
      rootContainerInstance,