Fix serving local_uploads during development

To serve uploaded crates during local development, the middleware must
serve the request before the ember rewrite occurs.  Additionally, these
requests should not affect the tally in the `BalanceCapacity`
middleware.

Author: jtgeibel

src/middleware.rs

@@ -47,8 +47,6 @@ pub fn build_middleware(app: Arc<App>, endpoints: R404) -> MiddlewareBuilder {
     if env == Env::Development {
         // Print a log for each request.
         m.add(Debug);
-        // Locally serve crates and readmes
-        m.around(StaticOrContinue::new("local_uploads"));
     }
 
     if env::var_os("DEBUG_REQUESTS").is_some() {
@@ -103,6 +101,11 @@ pub fn build_middleware(app: Arc<App>, endpoints: R404) -> MiddlewareBuilder {
         m.around(StaticOrContinue::new("dist"));
     }
 
+    if env == Env::Development {
+        // Locally serve crates and readmes
+        m.around(StaticOrContinue::new("local_uploads"));
+    }
+
     m.around(Head::default());
 
     for (header, blocked_values) in config.blocked_traffic {