Move DnsPacket to libs/net am: 2950a64eec

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/libs/net/+/11862584

Change-Id: Id5c94b8a7a4b9e7c59febc40caa114350ec2246a
tree: 4da58d92bccbfc5203f8c7d0164d8138c0ee1950
  1. common/
  2. .gitignore
  3. PREUPLOAD.cfg