Fix a tethering crash when a 464xlat upstream disconnects. am: a329e8c984 am: dadc2fe3bb

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1671533

Change-Id: Ia7e17399aa5da6bbb84419ef2d840cf14ee70ea9
tree: 0f6ec8e04c72ae5da4c0507e7718199bac6830ee
  1. tests/
  2. Tethering/
  3. .gitignore
  4. OWNERS
  5. PREUPLOAD.cfg
  6. TEST_MAPPING