Fix proguard rules for Struct in NetworkStack am: 9a82bbf368 am: 9aaeab539b am: 237561ebdf

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1674688

Change-Id: Id9ea41e2831af5a01e3088dc1d3feca89946c926
tree: d785781d58624b2dff971427db405d16b857eb8a
  1. tests/
  2. Tethering/
  3. .gitignore
  4. OWNERS
  5. PREUPLOAD.cfg
  6. TEST_MAPPING