Clean up options list callback on module disable

This is probably quite unlikely to happen, but it happened for us: We used the Module, customer decided to not use TAC any more, disabled the module and then we had a "function not found" on every node edit with a taxonomy reference field.

The Problem is, that TAC adds a new callback in taxonomy_access_field_info_alter() but never removes it again when the module is disabled.

Now the taxonomy_options_list function in drupal core does not check if the defined functions does exist and fails.

I already wrote a core patch #1358094: Function taxonomy_options_list() should check if function exists , but maybe you want also to take care about this problem?

Basically the best would be to remove the callback setting when disabling?