Avoid writing a minified file when --stdout is used. [closes #273]

Former-commit-id: 75068b4a92f3a98d4c47ad049e88ef764154bcc1

build.js

@@ -3183,11 +3183,10 @@
             data.source = addCommandsToHeader(data.source, options);
           }
           if (isStdOut) {
+            delete data.outputPath;
             stdout.write(data.source);
-            callback(data);
-          } else {
-            callback(data);
           }
+          callback(data);
         }
       });
     }