Remove Rust spinning square example

It needs to be updated for both the new FIDL bindings and Mozart 2 so it
is not a good example right now. I will bring it back when it makes sense
to have a Rust example of a Mozart client module in Topaz.

Change-Id: I7a4cd201895b92dae57173392cb4afbdc97e7fa2
diff --git a/update_rust_crates.py b/update_rust_crates.py
index a271239..ab0e975 100755
--- a/update_rust_crates.py
+++ b/update_rust_crates.py
@@ -30,11 +30,9 @@
     "garnet/public/rust/crates/tokio-fuchsia",
     "third_party/xi-editor/rust/core-lib",
     "topaz/app/xi/modules/xi-core",
-    "topaz/examples/spinning-square-rs",
 ]
 
 NATIVE_LIBS = {
-    "cairo": "//third_party/cairo",
 }