SpringBoot Remove Flyway references from AbstractDependsOnBeanFactoryPostProcessors for Liquibase

This PR removes FlywayMigrationInitializer references from AbstractDependsOnBeanFactoryPostProcessors for Liquibase as they seem to have been added accidentally.

Comment From: wilkinsona

Whoops. Thanks, @izeye. Those are indeed accidental.

Comment From: wilkinsona

Thanks again, @izeye.