title: Why does release:prepare change versions back to SNAPSHOT?
body: <p>I'm using the maven-release-plugin and I'm noticing that it appears to change the released version BACK to -SNAPSHOT at the end.</p>
  
  <p>Here's the command line args that I'm passing to maven:</p>
  
  <pre><code>--batch-mode release:prepare -DupdateWorkingCopyVersions=false -Darguments="-DskipTests -Djava.awt.headless=true -Dmaven.javadoc.failOnError=false"
  </code></pre>
  
  <p>Everything appears to go well - and I notice a commit and a push from the plugin where all of the proper version numbers are indeed updated to NOT have the -SNAPSHOT.</p>
  
  <pre><code>[WARNING] Ignoring unrecognized line: ?? myProject/pom.xml.releaseBackup
  </code></pre>
  
  <p>I see a few of these warnings ^ in the log file (not sure if this is relevant, but appears to be related to the release plugin)</p>
  
  <p>Finally I see that the plugin modifies the POMs again:</p>
  
  <pre><code>[INFO] Transforming 'myProject POM'...
  [INFO]   Updating my-project to 6.2-SNAPSHOT
  </code></pre>
  
  <p>Following this the plugin makes and pushes a commit with the following:</p>
  
  <pre><code>[maven-release-plugin] rollback changes from release preparation of myProject-6.2
  </code></pre>
  
  <p>Why is this last bit happening?</p>
  
  <p>I don't understand the lifecycle of release:prepare or release:perform.  Why does all of my code appear to be built twice? </p>
  
  <p>Any help appreciated. Thanks</p>