WebStyle: fix WSGI handler generated errors in apache.err

[tiborsimko]

Originally on 2011-01-19

WSGI handler generates lots of entries in apache.err like this:

[Wed Jan 19 15:15:04 2011] [error] /usr/local/lib/python2.6/dist-packages/invenio/webinterface_handler_wsgi_utils.py:368: DeprecationWarning: object.__init__() takes no parameters
[Wed Jan 19 15:15:04 2011] [error]   str.__init__(self, value)

It would be good to fix this in order not to overflow apache.err unnecessarily.

[kaplun]

Originally on 2011-02-22

The attached patch fixes the warning.

[invenio-developers]

Originally by Samuele Kaplun samuele.kaplun@cern.ch on 2011-02-22

In [69fe5e5]:

#CommitTicketReference repository="" revision="69fe5e5eb21c45747ebde843f0648f24293c8f8c"
WebStyle: fix StringField definition

- StringField in webinterface_handler_wsgi_utils is derived from
  the immutable str builtin type. In order to be initialized
  it requires appropriate usage of __new__ special method instead
  of __init__. (closes #451)