versionadded, versionchanged directives don't insert xref link with Sphinx 1.0

[Ramiro Morales]

It works correctly with Sphinx 0.6.x.

Refs. #13616 and #14005, this had already been reported by andrewsk (​http://code.djangoproject.com/ticket/13616#comment:8).

An example: ​http://docs.djangoproject.com/en/1.2/ref/models/options/#django.db.models.Options.managed

The fix is to replace 'ref' with 'std:ref' when adding the node but I to migrate the directive implementation to the class-based scheme available since sphinx 0.6 from the deprecated function-based (see ​http://sphinx.pocoo.org/ext/appapi.html#sphinx.application.Sphinx.add_directive)

[Ramiro Morales]

Path for this issue

[Ramiro Morales]

Fixed bare except clauses.

[Jannis Leidel]

(In [13602]) Fixed #14033 -- Fixed another problem with xrefs and Sphinx 1.X in the Django doc extension. Thanks for the report and patch, Ramiro Morales and Georg Brandl.

[Jannis Leidel]

(In [13603]) [1.2.X] Fixed #14033 -- Fixed another problem with xrefs and Sphinx 1.X in the Django doc extension. Thanks for the report and patch, Ramiro Morales and Georg Brandl.

Backport of r13602 from trunk.