Fix build.

tiny_mirrors no longer exists.

Change-Id: I5f24d0ca4ca44d5f5baf8325ba9e75c2989f01b7
diff --git a/Cargo.toml b/Cargo.toml
index 443e4f1..a6fc029 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,5 +18,5 @@
 structopt = { path = "rust_crates/vendor/structopt" }
 
 [patch.crates-io]
-winapi = { path = "rust_crates/tiny_mirrors/winapi" }
-winapi-util = { path = "rust_crates/tiny_mirrors/winapi-util" }
+winapi = { path = "rust_crates/empty/winapi" }
+winapi-util = { path = "rust_crates/empty/winapi-util" }