cleanup - remove send_tun()

Test:
  git grep send_tun
  comes up empty

Bug: 144730808
Test: atest clatd_test netd_integration_test
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Original-Change: https://android-review.googlesource.com/1322978
Merged-In: If81ca18bf5a33549b532de0d6406e32f4560c93a
Change-Id: If81ca18bf5a33549b532de0d6406e32f4560c93a
2 files changed