Description of problem:
When pulp is down (and possibly, changesets exist), user gets a really ugly dashboard message that we should probably make a little more user-friendly.

Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:

You may or may not have to create changesets for this to show up. Go ahead and do it....

1.  Create a new promotion changeset, "bugtest2" - add content, review it, but
do not yet promote
2.  Do something that would trigger a failure - this can be done by executing
`service mongod stop`
3.  Attempt to promote changeset; wait for failure  
4.  While mongod is still down, nav to the dashboard.

Actual results:
Error message in notification:

Pulp::Consumer: 500 Internal Server Error "Traceback (most recent call last):\n File \"/usr/lib/python2.6/site-packages/pulp/server/webservices/controllers/decorators.py\", line 48, in report_error\n return method(self, *args, **kwargs)\n File \"/usr/lib/python2.6/site-packages/pulp/server/webservices/controllers/decorators.py\", line 112, in _auth_decorator\n user = check_oauth(username, meth, url, auth, query)\n File \"/usr/lib/python2.6/site-packages/pulp/server/auth/authentication.py\", line 216, in check_oauth\n return _check_username_password_local(username)\n File \"/usr/lib/python2.6/site-packages/pulp/server/auth/authentication.py\", line 105, in _check_username_password_local\n user = _user_api.user(username)\n File \"/usr/lib/python2.6/site-packages/pulp/server/api/user.py\", line 92, in user\n users = self.users({'login': login}, fields)\n File \"/usr/lib/python2.6/site-packages/pulp/server/api/user.py\", line 85, in users\n users = list(self.collection.find(spec=spec, fields=fields))\n File \"/usr/lib/python2.6/site-packages/pulp/server/api/base.py\", line 32, in collection\n return self._getcollection()\n File \"/usr/lib/python2.6/site-packages/pulp/server/api/user.py\", line 31, in _getcollection\n return model.User.get_collection()\n File \"/usr/lib/python2.6/site-packages/pulp/server/db/model/base.py\", line 126, in get_collection\n return cls._get_collection_from_db()\n File \"/usr/lib/python2.6/site-packages/pulp/server/db/model/base.py\", line 102, in _get_collection_from_db\n _ensure_indices(collection, cls.unique_indices, True)\n File \"/usr/lib/python2.6/site-packages/pulp/server/db/model/base.py\", line 99, in _ensure_indices\n unique=unique, background=True)\n File \"/usr/lib/python2.6/site-packages/pulp/server/db/connection.py\", line 80, in retry\n return method(*args, **kwargs)\n File \"/usr/lib64/python2.6/site-packages/pymongo/collection.py\", line 713, in ensure_index\n ttl, **kwargs)\n File \"/usr/lib/python2.6/site-packages/pulp/server/db/connection.py\", line 89, in retry\n 

Expected results:
Handle such errors gracefully - provide some contextual clue that perhaps the pulp service is down.

Additional info: