Some stacks have not been updated since the rosdep 2 updates were
deployed several weeks ago.  We have to pull some of these stacks as
they cause spurious errors in the pre-release system as their
dependencies cannot be installed.

The number of pulled stacks is small.  We have attempted to merge most
existing rosdep.yaml files into the main rosdep 2 database to minimize
the effect, but we left some rules out because:

 1. They duplicate other rules and thus should be re-unified
 2. They don't follow the suggested naming convention of using the
Ubuntu package name
 3. They bundle multiple packages under one mega-rule

Not every key follows (2) or (3); updating the rosdep database and
related stacks will be a major undertaking for commonly used keys.
For lesser used keys, we've chosen to enforce 2+3 prior to the
official Fuerte release as updating the stack/rules is trivial and
will save a lot of effort down the road.

You can find documentation on contributing rules here:

http://ros.org/doc/api/rosdep2/html/contributing_rules.html

The new process makes use of Github pull requests and we've been able
to serve a number of requests already (and more quickly than in the
old system).

 - Ken