Block region selection in Drupal 4.6.2 is buggy

Block module has a IN('%s') SQL portion when selecting block regions, while block regions are numbers, so passing on multiple regions (as it is with the 'all' region parameter by default) results in IN('0, 1') and this is incorrect to match integers. Correct form is IN(0, 1).

Spotted while upgrading to Drupal 4.6.2. This might be a problem in HEAD too, since this seems to be related to the multiple block regions patch.