Code review comment for lp:~rvb/launchpad/db-distroseries-migrate-owner-to-registrant

A couple of minor things to mention:

1. The db patch can just rename the column instead of deleting/adding.
2. The chunk of added zcml in 'lib/lp/registry/configure.zcml is weirdly formatted in the diff here.

Nothing else leaps out at me, so unless Curtis sees a problem I'm ok with it.