Satellite 5.4 to 5.7 upgrade fails with "no matching unique or primary key for this column-list"

Issue

During an upgrade of Satellite from 5.4 to 5.7, the step to run spacewalk-schema-upgrade fails with the following in the log:

SATELLITE-SCHEMA-5.5-TO-SATELLITE-SCHEMA-5.6/008-RHNCONTENTSOURCESSL.SQL.ORACL
-------------------------------------------------------------------------------
satellite-schema-5.5-to-satellite-schema-5.6/008-rhnContentSourceSsl.sql.oracle

                constraint rhn_csssl_cacertid_fk references rhnCryptoKey(id),
                                                                         *
ERROR at line 10:
ORA-02270: no matching unique or primary key for this column-list