EDIT: You only need this module if you are using release 2.11 of the openlayers javacript library.
Check the version you are using here: admin/structure/openlayers
In version 2.12 the problem with the google terms-of-service popup does not occur.
This small D7 module provides a block which when added to an OpenLayers map page will fix the issue described here: http://drupal.org/node/1540534.
Install and enable the module.
Go to Structure > Blocks (admin/structure/block).
Add the openlayers-google-popup-fix block to one of your regions.
You will normally configure the block to only appear on the same pages that your OpenLayers map appears on.