am 8e6f821e: Avoid inheriting PRIVATE_BOOTCLASSPATH from moduels that depend on api-stubs-timestamp

Merge commit '8e6f821e733e075086cb80309717e3a85e2a9c37' into gingerbread-plus-aosp

* commit '8e6f821e733e075086cb80309717e3a85e2a9c37':
  Avoid inheriting PRIVATE_BOOTCLASSPATH from moduels that depend on api-stubs-timestamp