Unset $db in DboSource::read().

After calling $db->queryAssociatin(), it is necessary to unset db. 
This reverts commit 52d425737af584d33352ff0540dbf769006d82f5.
Remove x bit on files.

PHP files should not have executable permission set.
Merge pull request #3481 from okinaka/master

Unset $db in DboSource::read().
Hotfix for older baked templates regarding postLink()