upgrade.sh: PKs and FKs for creditable attributes
upgrade.sh: Match new track schema to CreateTables.sql
upgrade.sh: Add a row of example documentation for all link_type rows
Merge branch 'master' of github.com:metabrainz/musicbrainz-server

* 'master' of github.com:metabrainz/musicbrainz-server:
  Properly set +x on migrate-transclusion-table.pl
  Add proper schema qualification in the documentation CreateReplicationTriggers
  Fix up CAA sql scripts