title: Liquibase optimize changelog problem with integrity (ValidationFailedException: Validation Failed)
body: <p>After some time I would like to optimize <code>changelog</code> I use in my <code>Spring-Boot</code> application. I use <code>SQL</code> syntax in my liquibase files.</p>
  <p>I have updated some of the old sqls (without changing changeset name). And now I got:</p>
  <pre><code>    Caused by: liquibase.exception.ValidationFailedException: Validation Failed:
           37 change sets check sum
                classpath:db/changelog/db.changelog-master.sql::4::siewer was: 8:8560502cf93e550076df8a7dc82a45b6 but is now: 8:543d80fbaa5a5b468e56ac6ef4705e58
  </code></pre>
  <p>Is it possible to change old <code>changesets</code> and update <code>hashes</code> without executing the migration? I would like already in-use databases to work without changes (but to be able to get new migrations). At this moment when I start an application with fresh database everything is ok, but when I want to run app on already populated database I got errors.</p>
  <p>Any tips? Is this possible to be done?</p>