Code review comment for lp:~edwin-grubbs/launchpad/bug-99395-linking-sourcepackages-to-projects

Summary
-------

Make $sourcepackage/+edit-packaging a two step form since users are
confused by having to enter $project/$series.

Implementation details
----------------------

The launchpadform was displaying "(Optional)" next to readonly widgets,
which seems silly.
    lib/canonical/launchpad/webapp/launchpadform.py

Converted SourcePackageChangeUpstreamView to MultiStepView.
    lib/lp/registry/browser/sourcepackage.py
    lib/lp/registry/stories/distribution/xx-distribution-packages.txt

Added multistep info and info on creating a new series if needed.
    lib/lp/registry/templates/sourcepackage-edit-packaging.pt

Tests
-----

./bin/test -vv -t xx-distribution-packages.txt

Demo and Q/A
------------

* Open https://launchpad.dev/ubuntu/warty/+source/iceweasel/+edit-packaging
    * Enter a project name.
    * Click "Continue".
    * Select a series.
    * Click "Change".
    * Verify that the series has changed on the sourcepackage page.