RPM build fix (reverted CI changes which will need to be un-reverted or made conditional) and vendor Rust dependencies to make builds much faster in any CI system.

zeroidc/vendor/serde_json/tests/ui/parse_expr.rs

@@ -0,0 +1,5 @@
+use serde_json::json;
+
+fn main() {
+    json!({ "a" : ~ });
+}