Fix Rust docs build

Fixes #1270

rust/CHANGELOG.md

@@ -3,6 +3,7 @@
 # NEXT
 
 * Update h264-profile-level-id dependency to 0.2.0.
+* Fix docs build.
 
 # 0.13.0
 

worker/build.rs

@@ -2,11 +2,6 @@ use std::process::Command;
 use std::{env, fs};
 
 fn main() {
-    if env::var("DOCS_RS").is_ok() {
-        // Skip everything when building docs on docs.rs
-        return;
-    }
-
     // On Windows Rust always links against release version of MSVC runtime, thus requires
     // Release build here
     let build_type = if cfg!(all(debug_assertions, not(windows))) {
@@ -45,6 +40,11 @@ fn main() {
     )
     .expect("Failed to write generated Rust flatbuffers into fbs.rs");
 
+    if env::var("DOCS_RS").is_ok() {
+        // Skip everything when building docs on docs.rs
+        return;
+    }
+
     // Force forward slashes on Windows too so that is plays well with our tasks.py
     let mediasoup_out_dir = format!("{}/out", out_dir.replace('\\', "/"));