Fix structopt-derive/METADATA am: 7a5d9b3390 am: f7af03948a am: 51e0ea6cd3 am: c3da38a393 am: b998dce8f5

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/structopt-derive/+/1414006

Change-Id: I245c2fb85b50597a681d3a63e66a3f3d104a95b1