Import grpcio 0.6.0

And add metadata files using the following command:
get_rust_pkg.py --add3prf -v grpcio-0.6.0 -o grpcio

Test: none
Change-Id: I53cc0feb5c9d24eacb62331b968cab4ec85f60a6
diff --git a/scripts/lint-grpc-sys.sh b/scripts/lint-grpc-sys.sh
new file mode 100755
index 0000000..a3fc7e0
--- /dev/null
+++ b/scripts/lint-grpc-sys.sh
@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+clang-tidy grpc-sys/grpc_wrap.cc -- -Igrpc-sys/grpc/include -x c++ -std=c++11