Vue mode quoting anomaly

```<q-dialog v-model='PromptName'/>```

converts to:

```q-dialog(v-model="'PromptName'")```

which is not liked:
```VueCompilerError: v-model value must be a valid JavaScript member expression.```

To my mind it's valid javascript and node doesn't mind but it is a bit odd.

It only seems to happen with v-model  (maybe all v- attributes).
