check for key 'status' in node dictionary

the following error is fixed:

[Tue Nov 05 16:35:39 2013] [error] ERROR:puppetboard.app:Exception on / [GET]
[Tue Nov 05 16:35:39 2013] [error] Traceback (most recent call last):
[Tue Nov 05 16:35:39 2013] [error] File "/usr/lib/python2.6/site-packages/flask/app.py", line 1817, in wsgi_app
[Tue Nov 05 16:35:39 2013] [error] response = self.full_dispatch_request()
[Tue Nov 05 16:35:39 2013] [error] File "/usr/lib/python2.6/site-packages/flask/app.py", line 1477, in full_dispatch_request
[Tue Nov 05 16:35:39 2013] [error] rv = self.handle_user_exception(e)
[Tue Nov 05 16:35:39 2013] [error] File "/usr/lib/python2.6/site-packages/flask/app.py", line 1381, in handle_user_exception
[Tue Nov 05 16:35:39 2013] [error] reraise(exc_type, exc_value, tb)
[Tue Nov 05 16:35:39 2013] [error] File "/usr/lib/python2.6/site-packages/flask/app.py", line 1475, in full_dispatch_request
[Tue Nov 05 16:35:39 2013] [error] rv = self.dispatch_request()
[Tue Nov 05 16:35:39 2013] [error] File "/usr/lib/python2.6/site-packages/flask/app.py", line 1461, in dispatch_request
[Tue Nov 05 16:35:39 2013] [error] return self.view_functionsrule.endpoint
[Tue Nov 05 16:35:39 2013] [error] File "/usr/share/puppetboard/puppetboard/app.py", line 114, in index
[Tue Nov 05 16:35:39 2013] [error] for node in nodes:
[Tue Nov 05 16:35:39 2013] [error] File "/usr/lib/python2.6/site-packages/pypuppetdb/api/v3.py", line 115, in nodes
[Tue Nov 05 16:35:39 2013] [error] status=node['status'],
[Tue Nov 05 16:35:39 2013] [error] KeyError: u'status'