Fix main.js for node10

Author: nmattia

infra/default.nix

@@ -22,7 +22,7 @@ rec
   function-unsplash =
     pkgs.runCommand "build-lambda" {}
       ''
-        cp ${pkgs.wai-lambda.wai-lambda-js-wrapper} main.js
+        cp ${./main.js} main.js
         # Can't be called 'main' otherwise lambda tries to load it
         cp "${unsplashProxy}/bin/unsplash-proxy" main_hs
         mkdir $out

infra/main.js

@@ -89,10 +89,8 @@ exports.handler = function(event, context, callback) {
 
                 // Clean up the directory and finally reply
                 console.log("cleaning up");
-                fs.unlink(responseFile, (err) => {
-                    if (err) throw err;
-                    fs.rmdir(responseDir);
-                });
+                fs.unlinkSync(responseFile);
+                fs.rmdirSync(responseDir);
                 callback(null, response);
             }
         });