Merge change 1797 into donut

* changes:
  Remove tcpdump from the old location (it's now in system/xbin)
tree: 77fda9b0be2a7fb84d57074ec36169f39cbe5ece
  1. core/
  2. libs/
  3. target/
  4. tools/
  5. buildspec.mk.default
  6. cleanspec.mk
  7. envsetup.sh