fix empty lambda warning

Author: jaredh159

lib/serve.js

@@ -45,12 +45,13 @@ function createCallback(response) {
       );
     } else {
       if (
-        process.env.CONTEXT !== "production" ||
+        response.statusCode !== 204 &&
+        process.env.CONTEXT !== "production" &&
         !process.env.SILENCE_EMPTY_LAMBDA_WARNING
       )
         console.log(
           `Your lambda function didn't return a body, which may be a mistake. Check our Usage docs for examples (https://github.com/netlify/netlify-lambda#usage). 
-          If this is intentional, you can silence this warning by setting process.ENV.SILENCE_EMPTY_LAMBDA_WARNING to a truthy value or process.env.CONTEXT to 'production'`
+          If this is intentional, you can silence this warning by setting process.env.SILENCE_EMPTY_LAMBDA_WARNING to a truthy value or process.env.CONTEXT to 'production'`
         );
     }
     response.end();