Fixed double-quoted URL bug in MapAdapter.get_default_redirect

default redirecting generates double-quoted URLs

When I defined the following routing rules:
```python
url_map = Map([
    Rule('/<category>', defaults={'page': 1}, endpoint='category'),
    Rule('/<category>/page/<int:page>', endpoint='category')
])
```

what I expected is:
http://localhost:5000/ham%20egg/page/1
↓(redirection)
http://localhost:5000/ham%20egg

but werkzeug does:
http://localhost:5000/ham%20egg/page/1
↓(redirection)
http://localhost:5000/ham%2520egg