Code review comment for lp:~julian-edwards/launchpad/ppa-search-oops-bug-446157

= Summary =
Fix an oops when someone hand-hacks URLs searching PPAs.

== Proposed fix ==
We need to cope with a list value when expecting a string in the form data.
This is a trivial change in the view code, but I also filed a Foundations bugs
since we should be able to do this generically in the form setup.

== Pre-implementation notes ==
None, I suck.

== Tests ==
bin/test -cvvt xx-ubuntu-ppas

== Demo and Q/A ==
https://launchpad.dev/ubuntu/+ppas?name_filter=packages&name_filter=humanity

= Launchpad lint =

Checking for conflicts. and issues in doctests and templates.
Running jslint, xmllint, pyflakes, and pylint.
Using normal rules.

Linting changed files:
  lib/lp/soyuz/stories/ppa/xx-ubuntu-ppas.txt
  lib/lp/registry/browser/distribution.py