Upgrade rust/crates/xml-rs to 0.8.4 am: adee7a49d8 am: 34e83cf902 am: f6e86c2633 am: b041468558 am: 1478469642

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/xml-rs/+/1790991

Change-Id: Ia6854add68e7ff64950d14c2b0c55b02c9cc70a0