fix column names in versionable with Postgres

When using Postgres, the versionable behavior produces invalid column names for the *_ids and *_versions columns, because the foreign table name it uses as a prefix includes the Postgres schema name and a dot. This pull request uses getCommonName() instead of getName() for the table name when generating the column names, thus leaving off the schema prefix.

This replaces the pull request submitted a while back as #498.