title: Gradle delete task failing with "unable to delete file"
body: <p>I have the following delete task added to my build.gradle file:</p>
  
  <pre><code>task cleanExtra(type: Delete) {
      delete '../version.properties'
  }
  
  clean.dependsOn(cleanExtra)
  </code></pre>
  
  <p>Sometimes, when I call <code>gradle clean</code>, it will fail with "Unable to delete file: (...)/version.properties". But if I call the same clean task a second time, it will successfully delete the task.</p>
  
  <p>Why does this happen? Anyway to avoid it?</p>