Merge "Remove the usage of NETID_UNSET from Vpn.java" am: 0f114dff28 am: 22f8ded94a

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1653929

Change-Id: I5e2dbb8cc31939b1fdc8abc785cb43e9519513af