Fix delete query bug
Fix delete query bug

when deleting a query, the web-explorer will request url: /explorer-admin/1/delete, then the DeleteView will check if the user has permission to delete a query:
`explorer/views.py` line 73-77
```
    def has_permission(self, request, *args, **kwargs):
        perms = self.get_permission_required()
        handler = getattr(permissions, perms)  # TODO: fix the case when the perms is
                                               # not defined in permissions module.
        return handler(request, *args, **kwargs)
```
You can see here will call handler(request, *args, **kwargs).
But in `permissions.py`, the `change_permission` function is defined as:
```
def change_permission(request):
    return app_settings.EXPLORER_PERMISSION_CHANGE(request.user)
```
It is a bug I think.
this patch fix it.
groveco/django-sql-explorer,groveco/django-sql-explorer,epantry/django-sql-explorer,epantry/django-sql-explorer,groveco/django-sql-explorer,epantry/django-sql-explorer,groveco/django-sql-explorer