First DB schema migration in Pike ensures that all of the Ocata's data
migrations are completed (Iab993f93b4145a67ec2d6144acc61f2105586b3c). We
can then remove them from Pike's code.
The commit also removes checks that were being made in user messages
code. These are not needed as we're sure everything's migrated.
Change-Id: I882e953800c4f4473f175779b6a44ad55928db65