Install explicitly creates cache table

It may be better to use something like:

  $schema['cache_linode'] = drupal_get_schema_unprocessed('system', 'cache');
  $schema['cache_linode']['description'] = 'Cache table for the Linode module to store results from the API.;

As it's shorter, and will automagically follow any changes to the cache system. Also, the fields need real descriptions :)