* Suggest --copy-out if it is not used, cargo output files are found,
and env!("CARGO_OUT") is found in .rs files.
* Expect to see this warning for libsqlite3-sys and grpcio-sys,
which fit to the use case of --copy-out but they have locally
defined .bp files and non-original output files.
* Fix one pylint warning of extra long line.
Bug: 172299436
Test: run cargo with same flags for all rust/crates/*
Test: run cargo without --copy-out for anyhow, protobuf, clang-sys, etc.
Change-Id: Ic346c8e1146b1bb77e63c4cb12947f202b0f458e
60140756b8