title: Why gradle clean task starts all other non-default tasks?
body: <p>I have gradle set up and running. My <code>build.gradle</code> has 2 tasks defined inside:</p>
  
  <pre><code>task setVersion() {
      println('setVersion')
      //...
  }
  
  task setIntegrationEnv() {
      println('setIntegrationEnv')
      //...
  }
  </code></pre>
  
  <p>When I run</p>
  
  <pre><code>./gradlew clean
  </code></pre>
  
  <p>gradle runs both tasks <code>setVersion</code> and <code>setIntegrationEnv</code> and then it runs clean for all my modules (<code>app</code>, <code>cloud_module</code>) in that project, output:</p>
  
  <pre><code>Relying on packaging to define the extension of the main artifact has been deprecated and is scheduled to be removed in Gradle 2.0
  setVersion
  setIntegrationEnv
  :cloud_module:clean
  :app:clean
  
  BUILD SUCCESSFUL
  
  Total time: 14.18 secs
  </code></pre>
  
  <p>Why this happens, where this behavior is defined?</p>