title: aapt_rules.txt not found when build library with Proguard
body: <p>I have an Android lib and generate AAR file using <a href="https://developer.android.com/studio/projects/android-library.html" rel="nofollow noreferrer">android library plugin</a> and <a href="https://github.com/Vigi0303/fat-aar-plugin" rel="nofollow noreferrer">fat-aar-plugin</a>, but now I need obfuscate code and I write a few simple rules (keep class only) on my .pro file, and add <code>minifyEnabled true</code> on my build.gradle</p>
  
  <p>The problem is when try make the project and received this error:</p>
  
  <pre><code>Warning:Exception while processing task java.io.FileNotFoundException: /Users/ninja/Development/Projects/Android/Cloud/CloudSDK-Core-Android/build/intermediates/proguard-rules/debug/aapt_rules.txt (No such file or directory)
  Error:Execution failed for task ':CloudSDK-Core-Android:transformClassesAndResourcesWithProguardForDebug'.
  &gt; Job failed, see logs for details
  </code></pre>