function randomVersionId() {
      // Appears to have enough entropy for chunk version IDs
      // (Only has to be different than enough of its own previous versions that there's no writer
      // that thinks a new version is the same as an earlier one, not globally unique)
      return Math.random().toString(36).substring(2);
    }
Deletes a database from IndexedDB

@example
// DELETE DATABASE
// delete 'finance'/'test' value from catalog
idbAdapter.deleteDatabase('test', function {
  // database deleted
});

@param {string} dbname - the name of the database to delete from IDB
@param {function=} callback - (Optional) executed on database delete
@memberof IncrementalIndexedDBAdapter