adbd: check auth id.

When multiple auth requests come in (e.g. if someone connects over TCP
and USB, or if we send a USB request, and then kill adb and try again),
we need to disambiguate.

Bug: http://b/159061108
Test: manual
Change-Id: I0768dc3c1830456cb8cbd4395c23ef8f193cc420
3 files changed