[automerger skipped] Support setting the default interface to null again. am: 356cf6ab82 -s ours am: ee648e7c5a -s ours

am skip reason: Change-Id I5109d8da3aeb6c1f6523291d9e2ec92c64b5ad2d with SHA-1 42cecb0751 is in history

Change-Id: I53102631b3030ba3307c2ffe04d340c9421fc50b
tree: 383b74744be1be63e8bd7e62b7fb70b52491a1a5
  1. service-t/
  2. tests/