Android Studio 0.4: Could not find method jniDir()

When updating to Android Studio 0.4, which uses the android gradle plugin 0.7.0 and gradle 1.9, following error occurs:

org.gradle.api.internal.MissingMethodException: Could not find method jniDir() ...

which refers to the follwing lines in my build.gradle:

 tasks.withType(com.android.build.gradle.tasks.PackageApplication) { pkgTask ->
   pkgTask.jniDir new File(projectDir, 'native-libs')
 }

P.S.: These answers fixed all other upgrade issues for me:

1. https://stackoverflow.com/a/19496969/1137547
2. https://stackoverflow.com/a/19461162/1137547