removing the need for a /update/json request handler

[ghost]

As of Solr 4.0,
updates can be sent in json format via the default /update search handler.
If a user does not have the /update/json search handler the update will fail.

I have fixed this by changing line 309 in mysolr.py from

    url = urljoin(self.base_url, 'update/json')

to

    url = urljoin(self.base_url, 'update?wt=json')

in order to fix this. Should this change be global to everyone?
Thanks!