cargo2rulesmk.py: Build with cap-lints allow

Make sure we can generate rules for crates even if they are not
linter clean and request to have linter issues treated as errors.

Test: cd external/rust/crates/serde && path/to/cargo2rulesmk.py --run
Bug: None
Change-Id: Ifc40a9e21494c571f598f3d407fe394fcfffb9b3
1 file changed