TypeError: Cannot convert undefined or null to object

### Version
2.6.0

### Steps to reproduce
Installed with nuxt.js v 0.10.7
With 2.5.3. it's working fine.

I guess this might be a problem with `<nuxt-link> / <router-link>`

### What is expected?
Regular render?

### What is actually happening?
After build i get

`TypeError: Cannot convert undefined or null to object`