title: findbugs-maven-plugin doesn't do anything
body: <p>I don't get it... I want to enable findbugs report in a Maven 3 project site and did it by adding this to my pom.xml (As described <a href="http://mojo.codehaus.org/findbugs-maven-plugin/usage.html" rel="noreferrer">here</a>):</p>
  
  <pre><code>&lt;project&gt;
    ...
    &lt;reporting&gt;
      &lt;plugins&gt;
        &lt;plugin&gt;
          &lt;groupId&gt;org.codehaus.mojo&lt;/groupId&gt;
          &lt;artifactId&gt;findbugs-maven-plugin&lt;/artifactId&gt;
          &lt;version&gt;2.4.0&lt;/version&gt;
        &lt;/plugin&gt;
      &lt;/plugins&gt;
    &lt;/reporting&gt;
    ...
  &lt;/project&gt;
  </code></pre>
  
  <p>Then I ran <code>mvn site</code> but no report is generated. Interesting thing is when I use version 2.3.1 instead then a report is generated. But 2.3.2 or 2.4.0 doesn't work. When running <code>mvn site -X</code> then the relevant output is this:</p>
  
  <pre><code>[DEBUG] Inside canGenerateReport..... false 
  [DEBUG] canGenerate is false
  [DEBUG] class org.codehaus.mojo.findbugs.FindBugsGui isMavenReport: false
  [DEBUG] skip non MavenReport org.codehaus.mojo:findbugs-maven-plugin:2.4.0:gui
  </code></pre>
  
  <p>What is this <code>canGenerate</code> stuff? What's going wrong here?</p>