* Electron version: All
* Operating system: All

### Expected behavior

`process.versions.electron` should be non-configurable

### Actual behavior

```js
process.versions.electron = '99.99.99'
```

Code such as the above will override the Electron version which can stop third party modules correctly recognising the Electron version.

### How to reproduce

Run the code above^^

The reason this is an issue is that other versions such as `process.versions.node` can not be configured / changed.
atom/renderer/atom_sandboxed_renderer_client.cc
process.Set("windowsStore", true);
#endif
  
  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
  if (command_line->HasSwitch(switches::kGuestInstanceID))
    b.Set(options::kGuestInstanceID,
          command_line->GetSwitchValueASCII(switches::kGuestInstanceID));
}
void AtomSandboxedRendererClient::RenderFrameCreated(
    content::RenderFrame* render_frame) {
  new AtomSandboxedRenderFrameObserver(render_frame, this);
  RendererClientBase::RenderFrameCreated(render_frame);
}
void AtomSandboxedRendererClient::RenderViewCreated(
    content::RenderView* render_view) {
  RendererClientBase::RenderViewCreated(render_view);
}
void AtomSandboxedRendererClient::DidCreateScriptContext(
    v8::Handle<v8::Context> context,
    content::RenderFrame* render_frame) {
  RendererClientBase::DidCreateScriptContext(context, render_frame);
  
  
  if (!render_frame->IsMainFrame() && !IsDevTools(render_frame))
    return;
  auto* isolate = context->GetIsolate();
  v8::HandleScope handle_scope(isolate);
  v8::Context::Scope context_scope(context);