Needs to graceful apache on upgrade

[James Troup]

After upgrading to 2.1.0-0~79+201108221736~O.IS.10.04 (from
2.0.1-0ubuntu1), all our python-apache-openid using sites started to
fail. The error log looked like this:

| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] mod_python (pid=20157, interpreter='pad.ubuntu.com', phase='PythonHandler', handler=<bound method OpenIDTe
| amsLoginHandler.handle_request of <apache_openid.handlers.openidteams.handler.OpenIDTeamsLoginHandler object at 0x7fb99db395d0>>): Application error
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] ServerName: 'pad.ubuntu.com'
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] DocumentRoot: '/htdocs'
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] URI: '/openid/+login'
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] Location: '/'
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] Directory: None
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] Filename: '/htdocs'
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] PathInfo: '/openid/+login'
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] Traceback (most recent call last):
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] File "/usr/lib/python2.6/dist-packages/mod_python/importer.py", line 1537, in HandlerDispatch\n default=default_handler, arg=req, silent=hlist.silent)
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] File "/usr/lib/python2.6/dist-packages/mod_python/importer.py", line 1229, in _process_target\n result = _execute_target(config, req, object, arg)
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] File "/usr/lib/python2.6/dist-packages/mod_python/importer.py", line 1128, in _execute_target\n result = object(arg)
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] File "/usr/lib/python2.6/dist-packages/apache_openid/handlers/openid/handler.py", line 113, in handle_request\n # It's not always safe to redirect non-GET requests so we just
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] File "/usr/lib/python2.6/dist-packages/apache_openid/handlers/openid/login_action.py", line 42, in do\n 'openid_identifier': openid, 'allowed_ops': self.allowed_ops,
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] File "/usr/lib/python2.6/dist-packages/apache_openid/template.py", line 47, in render\n content = self.get_template(template) % self.fill_login_page(values)
| [Sun Mar 04 21:25:36 2012] [error] [client 91.189.88.12] KeyError: u'continue_btn'

Looking at the diff between versions
(http://paste.ubuntu.com/868992/), the problem became clear - the
cached running code in apache was out of sync with what the (uncached)
template expected. A simple 'apache2ctl graceful' fixed the problem.

Please fix the package to do this on upgrade; there's plenty of
precedent for this, see e.g. mod python's own postinst.