Problem/Motivation
Currently forum module trying to delete taxonomy_forums field in forum_uninstall() but this field could be used in other entities. Also forum node type is not deleted when forum uninstalled so it makes sense preserve all its fields as well
Proposed resolution
Remove field deletion from forum_uninstall()
Also this removes need in calling field_purge_batch() so uninstall will be quicker.
This does not affects re-install of the forum module because forum_enable() cares to re-create all needed entities and fields
API changes
no