title: generateChangelog ignores diffTypes="data"
body: <p>I run</p>
  
  <pre><code>liquibase generateChangeLog --diffTypes="data"
  </code></pre>
  
  <p>but it generates changelog file without any inserts, the same as without diffTypes.</p>
  
  <p>Properties:</p>
  
  <pre><code>driver=org.postgresql.Driver
  classpath=postgresql.jdbc.jar 
  url=jdbc:postgresql://localhost:5432/knightsaga
  username=postgres
  password=postgres
  # default changelog to use, relative to classpath
  changeLogFile=./changelogs/db.changelog.xml
  ### DIFF params ###
  referenceUrl=jdbc:postgresql://localhost:5432/knightsaga
  referenceUsername=postgres
  referencePassword=postgres
  </code></pre>
  
  <p>How to include data there?</p>