As said here db_link cannot be used with db_query.
I replace it with
$variables = db_select('variable', 'v')->fields('v', array('name'))->condition('name', db_like('openlayers_') . '%', 'LIKE')->execute()->fetchCol();
and it works fine.
This is the same for openlayers_ui and openlayers_views.

Comments

Version:7.x-2.0-beta1» 7.x-2.x-dev
Status:Active» Fixed

Good catch @igarbla. I thought I had tested that out. I didn't end up using that way of doing, but using the global $conf.
http://zzolo.org/thoughts/tip-managing-variables-drupal-module

http://drupalcode.org/project/openlayers.git/commit/f61b897

Status:Fixed» Closed (fixed)

Automatically closed -- issue fixed for 2 weeks with no activity.