Revert "pg_createsubscriber: Add log message when no publications exist to drop."

Revert "pg_createsubscriber: Add log message when no publications exist to drop."

This reverts commit 74ac377d75135e02064fc4427bec401277b4f60c.

The previous change contained a misconception about how publications
are cleaned up on the subscriber. The newly added log message could
confuse users, particularly when running pg_createsubscriber with
--dry-run - users would see a "dropping publication" message
immediately followed by a "no publications found" message.

Discussion: https://postgr.es/m/CAHut+Pu7xz1LqNvyQyvSHrV0Sw6D=e6T-Jm=gh1MRJrkuWGyBQ@mail.gmail.com