adbd: add logging to troubleshoot usb issues.

Bug: http://b/63899881
Bug: http://b/63901259
Bug: http://b/63904904
Test: treehugger
Change-Id: Ifbc3caa6b416093bf8e127194003747c910352dc
diff --git a/adb/adbd_auth.cpp b/adb/adbd_auth.cpp
index b5f87be..3488ad1 100644
--- a/adb/adbd_auth.cpp
+++ b/adb/adbd_auth.cpp
@@ -217,8 +217,8 @@
     send_packet(p, t);
 }
 
-void adbd_auth_verified(atransport *t)
-{
+void adbd_auth_verified(atransport* t) {
+    LOG(INFO) << "adb client authorized";
     handle_online(t);
     send_connect(t);
 }