Merge lp://staging/~edwin-grubbs/launchpad/bug-552619-suggesting-removed-packages into lp://staging/launchpad

Fix problem where the project index page would suggest linking to an ubuntu package that had been deleted.

Summary
-------

ubuntu.searchSourcePackages() was returning packages that are invalid
suggestions since it does not filter on the status of the entries in the
SourcePackagePublishingHistory table.

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

Instead of extending the search functionality, I matched the assertion
in the model by checking the SourcePackage.currentrelease for
ubuntu.currentseries. ubuntu.searchSourcePackages() actually returns
DistributionSourcePackage objects. The SourcePackage objects for the
currentseries is accessed as the development_version attribute on the
DistributionSourcePackage.

Tests
-----

./bin/test -vv -t product-portlet-packages-view

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

On launchpad.dev:
* Run this query on the launchpad_dev db:
  UPDATE sourcepackagepublishinghistory SET distroseries = 22, status=3;
  * Open http://launchpad.dev/firefox
    * There should be no packages suggested in the Packages in Ubuntu
      portlet.

On edge:
* Open https://edge.launchpad.net/waf
  * The "waf" package should not be suggested in the Packages in Ubuntu
    portlet.