Cannot install Replication Server 12.6 on top of Adaptive Server 15.0

[CRs #400506 and #400508] Installing Replication Server version 12.6 on top of Adaptive Server version 15.0 causes Replication Server to fail.

Workaround: Install either of the following:

Replication Server version 12.6 into a separate directory than Adaptive Server, or