add check to filter out custom scripts in eject command (facebook#2562)

Author: paweljedrzejczyk

packages/react-scripts/scripts/eject.js

@@ -169,6 +169,9 @@ inquirer
     Object.keys(appPackage.scripts).forEach(key => {
       Object.keys(ownPackage.bin).forEach(binKey => {
         const regex = new RegExp(binKey + ' (\\w+)', 'g');
+        if (!regex.test(appPackage.scripts[key])) {
+          return;
+        }
         appPackage.scripts[key] = appPackage.scripts[key].replace(
           regex,
           'node scripts/$1.js'