Merge "repo-pull: Introduce --ignore-unknown-changes arg" am: e4f118be6f

Original change: https://android-review.googlesource.com/c/platform/development/+/2544230

Change-Id: I1a893e625817888e3c576de68c509387d3c47cb0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>