am a96c501e: Mark ip-up-vpn as optional

Merge commit 'a96c501e99bc7de068540225102854994e30cad1' into gingerbread-plus-aosp

* commit 'a96c501e99bc7de068540225102854994e30cad1':
  Mark ip-up-vpn as optional
tree: d21eacefb448230b6cefda408a429fa92da6889f
  1. android/
  2. pppd/
  3. CleanSpec.mk