Update `drush cc all` to `drush cr`

`drush cc all` is now deprecated and doesn't work for Drupal 8.
Remove deletion of PhpStorage

`drush cr` takes care of this.
Remove `drush rr` call
Merge pull request #1 from Cottser/drush-cr

- Pull #1
  * Update `drush cc all` to `drush cr`