[2638] History path lost on Safari while using router.base on nuxt.config.js

Here are steps and requirements to reproduce:

• Any iOS device, tested on iOS11/10/9
• Nuxt 1.1.1

1. Install nuxt-starter-kit template
2. Add router configure in to nuxt.config.js ↓

router: {
  base: '/abc'
}

3. Create a.vue in pages directory, add <nuxt-link to="/b">To Page B</nuxt-link> in template
4. Create b.vue in pages directory, add any text into template
5. Open "http://you-host:your-port/abc/a"
6. Press "To Page B" button, after page loaded, press the back button

Actual result: It return to "http://your-host:your-port/abc" Excepted result: Should return to last page "http://your-host:your-port/abc/a"