Fix jump_to_id url

Kindly review this issue
@adampalay @waheedahmed @symbolist @waheedahmed  
I think it would be cleaner to do:
```
reverse('jump_to_id', kwargs={'course_id': course_id.to_deprecated_string(), 'module_id': ''})[:-1]
```

Also since now urls without slash at end would cause a redirect, we need to ensure that rendered urls have a slash at end. For that you can add a parameter `slash_at_end=False` to the function `replace_jump_to_id_urls`, pass `True` here and change line 70 to:

```
return "".join([quote, jump_to_id_base_url + rest + '/' if slash_at_end else '', quote])
```