MDL-29960 repository/dropbox - remove unsused code

This function calls an API request which may be changed from the
version 0 of the API

repository/dropbox/locallib.php

@@ -52,15 +52,6 @@ class dropbox extends oauth_helper {
         return $data;
     }
 
-    /**
-     * Get user account info
-     */
-    public function get_account_info($token, $secret) {
-        $url = $this->dropbox_api.'/account/info';
-        $content = $this->get($url, array(), $token, $secret);
-        return $content;
-    }
-
     /**
      * Download a file
      */